Authors:Miaodi Guo; Xuemei Su Abstract: We present a scheme to realize two-direction optical switch by a single-mode optical cavity containing some four-level atoms. The high switching efficiency can be obtained through low photon loss and large third-order nonlinear susceptibility of this N-type atomic system in cavity. Without the microwave source, it can be reduced to a Λ-type atomic system where a coupling laser is used to realize single intracavity electromagnetically induced transparency (EIT). Namely, the probe field can be transmitted almost totally at resonance. Thus a two-direction optical switch is operated and the state for forward (backward) direction is set as “open” (“closed”). When microwave source is introduced, dressed splitting of intracavity dark state happens. The probe field is reflected almost completely at resonance and the state of the optical switch at forward and backward directions (transmitted and reflected channels) is shifted as “closed” and “open”, respectively. Moreover, this scheme is much advantageous to realize splitting of intracavity dark state because weak microwave field (Ωm∼0.1γ14) induces the coupling between intracavity dark state and one sublevel of ground state. While a strong pump laser (Ωd≥γ14) which couples the intracavity dark state with an excited level is applied to realize this splitting in ref. [Phys. Rev. A 85 013814 (2012)].In this paper, the two-direction optical switch based on dressed intracavity dark states is proposed. High switching efficiency (0.98/0.94 for transmitted/reflected channel) can be obtained through large third-order nonlinear susceptibility of N-type atomic system in cavity. Based on the coupling between two sublevels of atomic ground state, this scheme is much advantageous to realize the splitting of intracavity dark state. PubDate: 2018-03-12T03:13:06.227213-05: DOI: 10.1002/andp.201700427

Authors:Ariel Caticha Abstract: Entropic Dynamics (ED) is a framework in which Quantum Mechanics (QM) is derived as an application of entropic methods of inference. The magnitude of the wave function is manifestly epistemic: its square is a probability distribution. The epistemic nature of the phase of the wave function is also clear: it controls the flow of probability. The dynamics is driven by entropy subject to constraints that capture the relevant physical information. The central concern is to identify those constraints and how they are updated. After reviewing previous work I describe how considerations from information geometry allow us to derive a phase space geometry that combines Riemannian, symplectic, and complex structures. The ED that preserves these structures is QM. The full equivalence between ED and QM is achieved by taking account of how gauge symmetry and charge quantization are intimately related to quantum phases and the single-valuedness of wave functions.The derivation of dynamics as an application of the method of maximum entropy hinges on identifying evolving constraints that capture the relevant physical information. Considerations from information geometry lead to a phase space geometry that combines Riemannian, symplectic, and complex structures. The Entropic Dynamics that preserves these structures is Quantum Mechanics. The argument casts new light on the connection between gauge symmetry, charge quantization, and the single-valuedness of wave functions. PubDate: 2018-03-12T03:12:46.447894-05: DOI: 10.1002/andp.201700408

Authors:S. Refki; S. Hayashi, H. Ishitobi, D.V. Nesterenko, A. Rahmouni, Y. Inouye, Z. Sekkat Abstract: Optical sensors based on surface plasmons have attracted much attention over the past decades owing to the wealth of applications in bio- and chemical and gas sensing. In surface plasmon resonance sensors, a single metal layer is commonly used, but its resolution is limited because of broad resonances. In this context, we have developed a sensor chip based on a stack of metals and a dielectric, e.g. a metal-insulator-metal structure, consisting of a thick insulator layer sandwiched by metal layers, that exhibits a sharp resonance due to the excitation of surface plasmon polaritons hybrid modes. We have performed both experiments and theoretical simulations to estimate the enhancement of the sensitivity of such a structure. By changing the refractive index of an aqueous solution of glucose on top of the sensor chip, we found that the use of a metal-insulator-metal structure improves the figure of merit of the sensor 7.5 times compared to that of a conventional surface plasmon resonance sensor chip.A highly sensitive and inexpensive optical sensor can be fabricated by using a stack of metal and dielectric layers; e.g. metal-insulator-metal structures which support hybrid plasmon modes that occur by interaction of the structure with laser light. Such modes are manifested by sharp resonances and strongly enhance the optical field and localize the light at the interface of the outer metal layer of the structure and the sensing medium. PubDate: 2018-03-12T03:12:31.054437-05: DOI: 10.1002/andp.201700411

Authors:Xiaoyu Xiong; Xueqian Zhang, Quan Xu, Quanlong Yang, Qiu Wang, Yuehong Xu, Huifang Zhang, Yanfeng Li, Jiaguang Han, Weili Zhang Abstract: Chiral responses are optical responses involving circular polarizations. Controlling the chiral response in a flexible way is very important in optical manipulations. Chiral metamaterials have thus drawn enormous interest due to their flexible designing feature. However, most of the previous studies are mainly realized by designing the structure of the individual meta-atom. Meanwhile, to enhance the response, complex design and fabrication processes are typically required. Here, by introducing spin-dependent propagating surface plasmons and spin-selective interference, giant spin-resolved transmission is achieved in a simple meta-hole structure. In this interaction process, spin-orbital angular momentum conversion plays an essential role. By controlling the phase difference between the interference components, controllable spin-resolved transmission is achieved. Furthermore, such method can also be applied to realize spin-resolved excitation of surface plasmons. The proposed controlling strategy offers a versatile platform for a variety of promising applications, such as polarization control, asymmetric transmission, surface plasmon excitation, and on-chip chiral manipulation.Surface plasmon mediated controllable spin-resolved transmission is demonstrated by designing spin-dependent surface plasmon (SP) scattering and spin-related interference using meta-hole structures, where spin and plasmonic angular momentums conversion processes are studied and carefully utilized. The phase of the excited SPs can be freely tuned by designing the metasurface structure, which enables the controllable feature. PubDate: 2018-03-12T03:12:14.657736-05: DOI: 10.1002/andp.201700364

Authors:Bo Liu; Yixiao Huang, Zhe Sun Abstract: We investigate the quantum temporal steering (TS), i.e., a temporal analogue of Einstein-Podolsky-Rosen steering, in a dephasing channel which is modeled by a central spin half surrounded by a spin-1/2 XY chain where quantum phase transition happens. The TS parameter STS and the TS weight WTS are employed to characterize the TS dynamics. We analytically obtain the dependence of STS on the decoherence factor. The numerical results show an obvious suppression of STS and WTS when the XY chain approaches to the critical point. In view of the significance of quantum channel, we develop a new concept, TS weight power, in order to quantify the capacity of the quantum channel in dominating TS behavior. This new quantity enables us to indicate the quantum criticality of the environment by the quantum correlation of TS in the coupled system.The quantum temporal steering (TS) problem in a quantum-critical environment is investigated. TS dynamics depends on the decoherence factor. Moreover, a new concept, TS weight power, is developed to highlight the role of the quantum channel in TS behavior. There exists an obvious suppression of the quantum steering when the environment approaches to the critical point. The sudden change points of TS indicate the quantum criticality very well. PubDate: 2018-03-07T02:25:35.620831-05: DOI: 10.1002/andp.201700373

Authors:Ming Hua; Ming-Jie Tao, Ahmed Alsaedi, Tasawar Hayat, Fu-Guo Deng Abstract: A one-step scheme is presented to construct the controlled-phase gate deterministically on remote transmon qutrits coupled to different resonators connected by a superconducting transmission line for an universal distributed quantum computing. Different from previous work on remote superconducting qubits, the present gate is implemented with coherent evolutions of the entire system in the all-resonance regime assisted by the dark photons to robust against the transmission line loss, which allows the possibility of the complex designation of a long-length transmission line to link lots of circuit QEDs. The length of the transmission line can reach the scale of several meters, which makes this scheme suitable for large-scale distributed quantum computing. This gate is a fast quantum entangling operation with a high fidelity of about 99%. Compared with previous work in other quantum systems for a distributed quantum computing, under the all-resonance regime, the present proposal does not require classical pulses and ancillary qubits, which relaxes the difficulty of its implementation largely.The first scheme for distributed quantum computing with remote superconducting qubits (SQs) is proposed. Its fidelity reaches 99%, the interaction between the remote qubits can be turned off conveniently, it does not need to populate realistic microwave photons in the superconducting transmission lines (TLs), and the length of the line reaches a scale of several meters, which allows a TL to link lots of remote circuit QEDs. PubDate: 2018-03-07T02:21:23.528873-05: DOI: 10.1002/andp.201700402

Authors:Hugo L. C. Couto; Ardiley T. Avelar, Wesley B. Cardoso Abstract: One-dimensional nonlinear Schrödinger equations are derived to describe the axial effective dynamics of cigar-shaped atomic repulsive Bose-Einstein condensates trapped with anharmonic transverse potentials. The accuracy of these equations in the perturbative, Thomas-Fermi, and crossover regimes were verified numerically by comparing the ground-state profiles, transverse chemical potentials and oscillation patterns with those results obtained for the full three-dimensional Gross-Pitaevskii equation. This procedure allows us to derive different patterns of 1D nonlinear models by the control of the transverse confinement even in the presence of an axial vorticity.The longitudinal dynamics of a cigar-shaped monoatomic Bose-Einstein condensate transversally trapped by an anharmonic potential can be accurately described by the 1D perturbative and Thomas-Fermi models valid in the perturbative interaction regime and in the strong interaction regime, respectively. In the crossover regime, there is not an effective model up to now. A new effective model made to fill this gap is developed in this paper. PubDate: 2018-03-07T02:20:58.028036-05: DOI: 10.1002/andp.201700352

Authors:Carolin Schmitz-Antoniak; Detlef Schmitz, Anne Warland, Masih Darbandi, Soumyajyoti Haldar, Sumanta Bhandary, Biplab Sanyal, Olle Eriksson, Heiko Wende Abstract: The Verwey transition in Fe3O4 nanoparticles with a mean diameter of 6.3 nm is suppressed after capping the particles with a 3.5 nm thick shell of SiO2. By X-ray absorption spectroscopy and its associated X-ray magnetic circular dichroism this suppression can be correlated to localized Fe2+ states and a reduced double exchange visible in different site-specific magnetization behavior in high magnetic fields. The results are discussed in terms of charge trapping at defects in the Fe3O4/ SiO2 interface and the consequent difficulties in the formation of the common phases of Fe3O4. By comparison to X-ray absorption spectra of bare Fe3O4 nanoparticles in course of the Verwey transition, particular changes in the spectral shape could be correlated to changes in the number of unoccupied d states for Fe ions at different lattice sites. These findings are supported by density functional theory calculations.The suppression of the Verwey transition by silica capping of 6 nm magnetite nanoparticles is investigated by X-ray absorption spectroscopy and correlated to localized Fe2+ states at the interface demonstrating the crucial role of the electronic structure for the Verwey transition. A reduced double exchange revealed by different site-specific spin canting behavior as well as changes in the electronic structure support this finding. PubDate: 2018-02-26T03:26:47.536986-05: DOI: 10.1002/andp.201700363

Abstract: In article number 1700256, Emanuele Verrelli and co-workers propose that cluster beam deposition of sub-2nm magic number Au clusters, Au20 and Au55, on flat surfaces reveals a rich evolution of the phenomena taking place at substrate level. New magic number clusters have been formed via coalescence of neighbouring clusters, such as Au561. Experimental and simulation results reveal that neighbouring clusters on the substrate coalesce only when the distance from their nearest neighbour cluster is below a critical mark of 0.5 nm. PubDate: 2018-02-16T03:52:59.778872-05: DOI: 10.1002/andp.201870013

Abstract: An ultrathin microlens array based on the geometric metasurface is reported by Jinjin Jin and co-workers in article number 1700326. The mirolens array is composed of a serial of subwavelength gratings with different rotation angles, possessing ultrathin, flat and broadband properties. Simultaneously, the focus lights modulated by the ultrathin microlens have high intensity uniformity. This ultrathin microlens possesses significant potential application in three-dimensional information storage. PubDate: 2018-02-16T03:52:55.570889-05: DOI: 10.1002/andp.201870015

Authors:Arianna Borrelli Abstract: This contribution looks back at the papers published fifty years ago by Abdus Salam and Steven Weinberg, which are today regarded as marking the coming-to-be of the Weinberg-Salam model of electroweak interactions. Despite their present fame, at the time of their publication the papers went largely unnoticed. Reconstructing the historical context from which they emerged will show how, against the traditional image of theoretical physicists as “lone geniuses,” the Weinberg-Salam model actually came to be thanks to the interplay of many different actors and ideas. PubDate: 2018-02-02T07:20:51.792144-05: DOI: 10.1002/andp.201700454

Authors:Salvatore Capozziello; Richard Pincak, Kabin Kanjamapornkul, Emmanuel N. Saridakis Abstract: A Chern-Simons current, coming from ghost and anti-ghost fields of supersymmetry theory, can be used to define a spectrum of gene expression in new time series data where a spinor field, as alternative representation of a gene, is adopted instead of using the standard alphabet sequence of bases A,T,C,G,U. After a general discussion on the use of supersymmetry in biological systems, we give examples of the use of supersymmetry for living organism, discuss the codon and anti-codon ghost fields and develop an algebraic construction for the trash DNA, the DNA area which does not seem active in biological systems. As a general result, all hidden states of codon can be computed by Chern-Simons 3 forms. Finally, we plot a time series of genetic variations of viral glycoprotein gene and host T-cell receptor gene by using a gene tensor correlation network related to the Chern-Simons current. An empirical analysis of genetic shift, in host cell receptor genes with separated cluster of gene and genetic drift in viral gene, is obtained by using a tensor correlation plot over time series data derived as the empirical mode decomposition of Chern-Simons current.Supersymmetry and spinor fields are adopted to describe particles and gravitational field in a comprehensive and unitary theory. Besides this standard approach, spinor fields are useful tools to represent the gene expression instead of the alphabet sequence of bases in DNA and RNA. The approach gives the possibility to describe the dynamics of genetic variations in viruses and proteins. As an example, we consider the HIV virus. PubDate: 2018-01-29T07:16:56.242216-05: DOI: 10.1002/andp.201700271

Authors:Zhi-Rou Liu; Tzonelih Hwang Abstract: This paper proposes a new semi-quantum key distribution protocol, allowing two “classical” participants without sophisticated quantum capability to establish a shared secret key under an untrusted third party (a quantum server). The proposed protocol is free from several well-known attacks. Furthermore, the efficiency is better than the existing three-party SQKD protocol in which the classical participants must have the quantum measurement capability.Liu and Hwang propose a new semi-quantum key distribution (SQKD) protocol, allowing two “classical” participants without sophisticated quantum capability to establish a shared secret key under an untrusted third party (a quantum server). The proposed protocol is free from several well-known attacks. Furthermore, the efficiency is better than the existing three-party SQKD protocol in which the classical participants must have the quantum measurement capability. PubDate: 2018-01-29T07:15:30.426847-05: DOI: 10.1002/andp.201700206

Authors:Ye-Hong Chen; Zhi-Cheng Shi, Jie Song, Yan Xia, Shi-Biao Zheng Abstract: In this paper, a method to accelerate population transfer by designing nonadiabatic evolution paths is proposed. We apply the method to realize robust and accelerated population transfer with a transmon qutrit. By numerical simulation, we show that this method allows a robust population transfer between the ground states in a Λ system. Moreover, the total pulse area for the population transfer is low as 1.9π that verifies the evolution is accelerated without increasing the pulse intensity. Therefore, the method is easily implementable based on the modern pulse shaper technology and it provides selectable schemes with interesting applications in quantum information processing.The paper theoretically studies a selectable method to realize fast and robust population transfer between the ground states of a transmon qutrit through designing a Hamiltonian to drive a quantum system to evolve along a quantum adiabatic-like process. PubDate: 2018-01-23T01:55:22.974131-05: DOI: 10.1002/andp.201700351

Authors:M. de Dios-Leyva; M. A. Hernández-Bertrán, A. L. Morales, C. A. Duque, Huynh Vinh Phuc Abstract: A detailed study of the magneto-optical absorption β(ℏω) is presented for graphene superlattices (SLs) subjected to a perpendicular magnetic field. For a given temperature, this quantity exhibits a resonant peak structure whose characteristics depend on the magnetic field regime, circular polarization of light and SL barrier height. For the intermediate field regime, we demonstrated that the resonant peak structure of β(ℏω) is directly correlated to the partial joint density of states. Specifically, the latter exhibits van Hove-like singularities and peaks at energies where β(ℏω) takes its maximum values. We also investigated the magnetoabsorption in the weak field regime for SLs exhibiting one and extra Dirac points in the absence of the field. It was found that for SLs with only one Dirac point, the absorption spectra consist of resonant peaks satisfying the same circular polarization dependent selection rule as that for pristine graphene, except for one of them. For SLs with extra Dirac points, the resonant peaks arise from transitions between singlet subbands or between doublet subbands and satisfy a circular polarization and peak intensity dependent selection rule. It was also found that the resonant structure of β(ℏω) can be observed experimentally at room temperature in clean SLs.In this work we report a theoretical study of the optical absorption in graphene superlattices with rectangular potential profile considering the effects of temperature and external magnetic field, which is applied perpendicularly to the system. The model calculation involves a diagonalization procedure with a base of harmonic oscillator functions. The magneto-optical absorption is calculated for right- and left-handed polarizations of the incident photon. PubDate: 2018-01-12T03:11:20.279579-05: DOI: 10.1002/andp.201700414

Authors:Andrey Novitsky; Taavi Repän, Sergei V. Zhukovsky, Andrei V. Lavrinenko Abstract: Recently it has been shown that plasmonic effects in hyperbolic metamaterials may facilitate overcoming the diffraction limit and enhance the contrast function of an image by filtering background radiation. Unfortunately, the contrast function of such a dark-field hyperlens degrades in the deep-subwavelength regime. We push forward the concept of the contrast function revival in the subwavelength imaging by introduction of the proper phase difference between coherent sources. To study this effect we develop a simplified theory of the wave propagation through a hyperbolic metamaterial and show that, in principle, two sources standing apart at any subwavelength distance can be distinguished. We suggest two feasible designs, the first of which employs the obliquely incident light, while the second one is based on a properly designed metasurface. The concept can be used in high-contrast subwavelength microscopy.Two objects placed at any subwavelength distance can be distinguished at the image plane, if their radiation is coherent and carries appropriately engineered phases. Such an improvement of the contrast function can be achieved for planar and cylindrical dark-field hyperlenses and experimentally realized using the obliquely incident plane waves. PubDate: 2018-01-12T03:11:02.653974-05: DOI: 10.1002/andp.201700300

Authors:Sebastian Tölle; Michael Dzierzawa, Ulrich Eckern, Cosimo Gorini Abstract: In ferromagnet/normal-metal bilayers, the sensitivity of the spin Hall magnetoresistance and the spin Nernst magnetothermopower to the boundary conditions at the interface is of central importance. In general, such boundary conditions can be substantially affected by current-induced spin polarizations. In order to quantify the role of the latter, we consider a Rashba two-dimensional electron gas with a ferromagnet attached to one side of the system. The geometry of such a system maximizes the effect of current-induced spin polarization on the boundary conditions, and the spin Hall magnetoresistance is shown to acquire a non-trivial and asymmetric dependence on the magnetization direction of the ferromagnet.In ferromagnet/normal-metal bilayers, the sensitivity of the spin transport coefficients to boundary conditions at the interface strongly depends on current-induced spin polarizations. In order to quantify the role of the latter, a Rashba two-dimensional electron gas with a ferromagnet attached to one side of the system is investigated. The spin Hall magnetoresistance is found to acquire a non-trivial dependence on the magnetization direction. PubDate: 2017-12-28T06:26:19.299747-05: DOI: 10.1002/andp.201700303

Authors:Kasra Rouhi; Hamid Rajabalipanah, Ali Abdolali Abstract: Here, for the first time, the real-time and broadband manipulation of terahertz (THz) waves are acquired by introducing a multifunctional graphene-based coding metasurface (GBCM). The designed structure consists of subwavelength patterned graphene units whose operational statuses can be dynamically switched between two digital states of “0” and “1”. By engineering the spatial distribution of chemical potentials across the GBCM, various scattering patterns having single, two, four, and numerous reflection beams are elaborately achieved just within one planar structure. To compute the far-field pattern of GBCM, an inverse discrete Fourier transform (IDFT) is established, providing a fast and efficient design method. The proposed GBCM provides a low reflection bellow −10 dB over a broad frequency band ranging from 1 THz to 1.9 THz. In addition, the metasurface retains its low reflection behavior in a wide range of incident wave angles for both TE and TM polarizations. According to conformal invariance of graphene sheets, the stealth property of GBCM is well preserved while wrapping around a curved object. The proposed technique of real-time scattering manipulation leads to multifunctional THz devices, opening new routes contributing to numerous applications such as imaging and stealth technology.The real-time manipulation of terahertz waves is revolutionary introduced by designing a versatile conformal graphene-based coding metasurface. Thanks to tunable property of graphene, diverse scattering patterns having single, two, four and numerous reflection beams are elaborately attained. The structure retains its low reflection in a wide frequency range from 1 THz to 1.9 THz under differently polarized oblique incidences. The proposed stratgy of THz wave manipulation offers many promising applications. PubDate: 2017-12-27T04:07:11.420309-05: DOI: 10.1002/andp.201700310

Authors:Junfeng Liu; Yiqi Zhang, Hua Zhong, Jingwen Zhang, Rong Wang, Milivoj R. Belić, Yanpeng Zhang Abstract: We investigate the propagation of a dual Airy beam in Hermitian and non-Hermitian waveguides, theoretically and numerically. Optical Bloch oscillations (OBOs) of the beam are demonstrated during propagation in both types of waveguides, and the numerical OBO period is found to be in accordance with the theoretical predictions. The two branches of the dual Airy beam do not display translational symmetry — the peaks will form in one branch only, due to the desynchronized Bragg reflection of the lobes. In the non-Hermitian waveguides, the dual Airy beam will be damped or amplified during propagation — depending on the imaginary part of the complex potential, which may provide loss or gain to the beam. In the PT-symmetric-like potential, the dual Airy beam may undergo amplification during propagation, but the total power will exhibit a stair-like behavior. The non-reciprocity is also exhibited by the dual Airy beam in such a potential. We believe that our research not only provides a new geometry for optical switches but also deepens the understanding of OBO in dual Airy beams.Dual Airy beam exhibits optical Bloch oscillation during propagation in the waveguide array with a transverse gradient. The oscillation of the two branches is different, because the secondary lobes of the left branch reach the Bragg reflection point earlier than the main lobe and interfere with it, causing the appearance of peaks in the left branch. This does not happen with the lobes of the right branch, which reflect synchronously. PubDate: 2017-12-27T04:06:28.098084-05: DOI: 10.1002/andp.201700307

Authors:Liyang Yue; Bing Yan, James N. Monks, Rakesh Dhama, Zengbo Wang, Oleg V. Minin, Igor V. Minin Abstract: A particle can function as a refractive lens to focus a plane wave, generating a narrow, high intensive, weak-diverging beam within a sub-wavelength volume, known as the ‘photonic nanojet’. It is known that apodization method, in the form of an amplitude pupil-mask centrally situated on a particle-lens, can further reduce the waist of a photonic nanojet, however, it usually lowers the intensity at the focus due to blocking the incident light. In this paper, the anomalously intensity-enhanced apodization effect was discovered for the first time via numerical simulation of focusing of the axially illuminated circular-column particle-lenses, and a greater than 100% peak intensity increase was realised for the produced photonic nanojets.The anomalously intensity-enhanced apodization effect was discovered for the first time via numerical simulation of focusing of the axially illuminated circular-column particle-lenses, and a greater than 100% peak intensity increase can be realised for the produced photonic nanojets due to convergence of power flows and analogy of increase of effective refractive index for the particle-lens material. PubDate: 2017-12-27T04:00:46.099446-05: DOI: 10.1002/andp.201700384

Authors:Karol A. Penson; Katarzyna Górska, Andrzej Horzela, Giuseppe Dattoli Abstract: We introduce and study an extension of the heat equation relevant to relativistic energy formula involving square root of differential operators. We furnish exact solutions of corresponding Cauchy (initial) problem using the operator formalism invoking one-sided Lévy stable distributions. We note a natural appearance of Bessel polynomials which allow one to obtain closed form solutions for a number of initial conditions. The resulting diffusion is slower than the non-relativistic one, although it still can be termed a normal one. Its detailed statistical characterization is presented in terms of exact evaluation of arbitrary moments and kurtosis and is compared with the non-relativistic case.A quasi-relativistic heat equation is postulated as emerging from the Wick rotation performed on the quasi-relativistic Schrödinger, i.e. Salpeter, equation with subtracted rest energy. The equation in 1 + 1 dimensions is studied with the use of the formalism based on properties of Bessel polynomials. The initial Cauchy problem is exactly solved and compared with corresponding non-relativistic solutions. Our solution shows that the quasi-relativistic diffusion is slower than the non-relativistic one. PubDate: 2017-12-22T02:04:52.396227-05: DOI: 10.1002/andp.201700374

Authors:Shang Sun; Zhenxing Zhou, Chen Zhang, Wenhong Yang, Qinghai Song, Shumin Xiao Abstract: Wide-bandgap material based all-dielectric metasurfaces have been ideal platforms for the realization of arbitrary phase control in visible spectrum. While TiO2 metasurfaces are very promising in broadband and high-efficiency anomalous transmission, meta-hologram, and meta-lenses et al., the current realizations are strongly dependent on the sophisticated fabrication technique to fabricate TiO2 nano-pillars with aspect ratio > 10. Herein we experimentally demonstrate a much simpler approach to realize efficient phase control of visible light. By exploiting TiO2 nano-blocks as meta-atoms on a ground metal plane, we find that TiO2 metasurface with aspect ratio around 1-1.5 is good enough to produce phase changes covering -π to π and high reflection efficiency simultaneously. Based on the phase control of the meta-reflectarray, anomalous reflection with a ratio between anomalous reflection and normal reflection ∼ 74/26 have been experimentally realized using a combination of typical electron-beam lithography, electron-beam evaporation, and a simple lift-off process. Similarly, high performance TiO2 metasurface in form of hologram has also been demonstrated for red (633 nm), green (520 nm), and blue (445 nm) wavelengths. We believe this research shall route a new way to cost-effective all-dielectric metasurfaces and advance their applications in encryption, anti-counterfeiting, and wearable displays.In our study, TiO2 nano-blocks as meta-atoms on a ground metal plane with aspect ratio around 1-1.5 can provide efficient full phase control. Using a combination of typical electron-beam lithography, electron-beam evaporation, and a simple lift-off process, high performance TiO2 metasurface in form of anomalous reflection and hologram has been demonstrated for visible wavelengths. PubDate: 2017-12-07T09:13:06.665714-05: DOI: 10.1002/andp.201700418

Authors:Vidar Gudmundsson; Nzar Rauf Abdulla, Anna Sitek, Hsi-Sheng Goan, Chi-Shung Tang, Andrei Manolescu Abstract: We show that a Rabi-splitting of the states of strongly interacting electrons in parallel quantum dots embedded in a short quantum wire placed in a photon cavity can be produced by either the para- or the dia-magnetic electron-photon interactions when the geometry of the system is properly accounted for and the photon field is tuned close to a resonance with the electron system. We use these two resonances to explore the electroluminescence caused by the transport of electrons through the one- and two-electron ground states of the system and their corresponding conventional and vacuum electroluminescense as the central system is opened up by coupling it to external leads acting as electron reservoirs. Our analysis indicates that high-order electron-photon processes are necessary to adequately construct the cavity-photon dressed electron states needed to describe both types of electroluminescence.The authors study both the conventional and the ground state electroluminescence caused by electron transport through an anisotropic multi level system of two parallel quantum dots in a photon cavity as the electron-photon interaction is enhanced by a Rabi resonance caused either by the usual para- or the less used diamagnetic interaction. The type of the Rabi resonance is chosen by the polarization of the cavity photons. PubDate: 2017-12-07T05:42:30.27688-05:0 DOI: 10.1002/andp.201700334

Authors:Kwang-Hyon Kim Abstract: This work reports giant optical nonlinearity of active gain composites containing metal nanoparticles. In the epsilon-near-zero regime, the effective index of the composite strongly depends on the magnitude of host material's saturable gain and one can obtain unity-order nonlinear optical index change for the pump with gain saturation intensity. For pump intensity of about 100 kW/cm2, the nonlinear refractive index (the refractive index change per unit pump intensity) reaches 10−5 cm2/W, which is 6–8 orders-of-magnitude larger than the records recently obtained in epsilon-near-zero bulk materials. If the gain value of the host medium is slightly larger than a critical value, such large optical nonlinearity can be obtained without loss or even accompanying with amplification. The proposed materials also have the advantage of wide tunability of operating wavelength range from visible to infrared by changing the gain value of the host and the shape parameters and filling factors of metal nanoparticles.In epsilon-near-zero regime, the effective indices of dye-doped dielectric composites containing metal nanoparticles strongly depend on the saturable gain of host material and one can obtain unity-order index change for pump intensity of about 100 kW/cm2. Nonlinear refractive index reaches 10−5 cm2/W, 6–8 orders-of-magnitude larger than the recently reported records. By properly adjusting the gain of the host, such nonlinearity can be obtained without loss or even accompanying with amplification. PubDate: 2017-11-29T07:36:18.484223-05: DOI: 10.1002/andp.201700259

Authors:Zhong-Xiao Wang; Yong-Pan Gao, Tie-Jun Wang, Chuan Wang Abstract: Gaussian steering is used to characterize the intrinsic quantum correlation of Gaussian states under Gaussian measurement. Here we study the generation of one-way Gaussian steering and the conversion of one-way Gaussian steering. It is found that one-way Gaussian steering could be generated by using Gaussian channels, either the Gaussian lossy channel or the Gaussian amplification channel. Exploiting the one-way Gaussian steering in a two-partite quantum system consists of two subsystems marked with A and B, one-way Gaussian steering (steering from A to B) can be converted to the other one-way Gaussian steering (steering from B to A) using linear optics, and vice versa.Here the generation of one-way Gaussian steering and the conversion of one-way Gaussian steering could be realized using linear optics. The one-way Gaussian steering could be generated by using Gaussian channels, either the Gaussian lossy channel or the Gaussian amplification channel. Exploiting the one-way Gaussian steering in a two-partite quantum system consists of two subsystems marked with A and B, one-way Gaussian steering (steering from A to B) can be converted to the other one-way Gaussian steering (steering from B to A) using linear optics, and vice versa. PubDate: 2017-11-28T09:26:12.708266-05: DOI: 10.1002/andp.201700328

Authors:Rafael Augusto Couceiro Correa; Davi Monteiro Dantas, Pedro Henrique Ribeiro da Silva Moraes, Alvaro Souza Dutra, Carlos Alberto Santos Almeida Abstract: This work aims to analyse the so-called configurational entropy in the Weyl pure geometrical thick brane model. The Weyl structure plays a prominent role in the brane thickness of this model. We find a set of parameters associated to the brane width where the configurational entropy exhibits critical points. The information-theoretical measure sets bounds into parameter of Weyl pure geometrical brane model. In addition, we also argue that a similar approach can be useful to analyze the corrections to Newtonian and Coulombian potentials in Weyl scenarios.In this work, we study the configurational entropy (CE) in the Weyl pure geometrical thick brane model. The Weyl structure plays a prominent role in the brane thickness of this model. This graphical abstract denotes the brighter areas where the model parameters denote unstable points (maximum CE), while the darken regions denote stable points (minimum CE). PubDate: 2017-11-28T09:22:03.89461-05:0 DOI: 10.1002/andp.201700188

Authors:Mina Noori; Mohammad Soroosh, Hamed Baghban Abstract: A comprehensive review considering recent advances in self-collimation and its applications in optical integration is covered in the current article. Self-collimation is compared to the conventional technique of photonic bandgap engineering to control the light propagation in photonic crystal-based structures. It is fully discussed how the self-collimation phenomenon can be tailored to be independent of the incident angle and polarization. This adds substantial flexibility to the structure to overcome light coupling challenges and simultaneously aids in the omission of bulk and challenging elements, including polarizers and lenses from optical integrated circuits. Additionally, designed structures have the potential to be rescaled to operate in any desired frequency range thanks to the scalability rule in the field of electromagnetics. Moreover, it is shown that one can boost the coupling efficiency by applying an anti-reflection property to the structure, which provides not only efficient index matching but also the matching between external waves with uniform amplitude and Bloch waves with periodic amplitude.Here, a comprehensive review of recent advances in self-collimation and its importance in optical integration is covered. Self-collimation is compared to photonic band gap engineering in photonic crystal structures. It is also discussed how self-collimation phenomenon can be engineered to be independent of incident angle and polarization. Moreover, it is shown that coupling efficiency can be enhanced by applying anti-reflection to the structure which provides efficient index matching mechanism. PubDate: 2017-11-28T09:21:48.572309-05: DOI: 10.1002/andp.201700049

Authors:Robert J. Nemiroff Abstract: When an object moves faster than emissions it creates, it may appear at two positions simultaneously. The appearance or disappearance of this bifurcation is referred to as a pair event. Inherently convolved with superluminal motion, pair events have no subluminal counterparts. Common examples of superluminal motions that exhibit pair events include Cherenkov radiation, sonic booms, illumination fronts from variable light sources, and rotating beams. The minimally simple case of pair events from a single massive object is explored here: uniform linear motion. A pair event is perceived when the radial component of the object's speed toward the observer drops from superluminal to subluminal. Emission from the pair creation event will reach the observer before emission from either of the two images created. Potentially observable image pair events are described for sonic booms and Cherenkov light. To date, no detection of discrete images following a projectile pair event have ever been reported, and so the pair event nature of sonic booms and Cherenkov radiation, for example, remains unconfirmed. Recent advances in modern technology have made such pair event tracking feasible. If measured, pair events could provide important information about object distance and history.To an observer, a passing object moving faster than emissions it creates is shown to appear at two positions at once. Discussed examples include Cherenkov radiation and supersonic airplanes. PubDate: 2017-11-28T09:20:28.018944-05: DOI: 10.1002/andp.201700333

Authors:Alexander Jarjour; Jon W. Cox, William T. Ruane, Holger Wenckstern, Marius Grundmann, Leonard J. Brillson Abstract: Ohmic and rectifying metal contacts to semiconductor nanowires are integral to electronic device structures and typically require different metals and different process techniques to form. Here we show how a noble metal ion beam of Pt commonly used to pattern conducting contacts in electron microscopes can form both ohmic and Schottky/blocking contacts on ZnO nanowires by controlling native point defects at the intimate metal-semiconductor interface. Spatially-resolved cathodoluminescence spectroscopy on a nanoscale both laterally and in depth gauges the nature, density, and spatial distribution of specific native point defects inside the nanowires and at their metal interfaces. Combinations of electron and ion beam deposition, annealing, and sculpting of the same nanowire provide either low contact resistivity ohmic contacts or a high Schottky/blocking barrier with a single metal source. These results highlight the importance of native point defects distributed inside nanowires and their variation near interfaces with sculpting and annealing.Native point defects inside ZnO nanowires can be used to produce both ohmic and Schottky contact behaviors from a single applied metal on the same nanowire. Besides highlighting the importance of defects and advancing our understanding of metal contacts to nanowires, it demonstrates how scanning electron microscopes equipped with just Pt gas injection can produce both types of contacts without the need to pattern multiple metal deposits or implant dopants. PubDate: 2017-11-28T09:15:51.076152-05: DOI: 10.1002/andp.201700335

Authors:Chandrachur Chakraborty; Oindrila Ganguly, Parthasarathi Majumdar Abstract: We report an incipient exploration of the Lense-Thirring precession effect in a rotating acoustic analogue black hole spacetime. An exact formula is deduced for the precession frequency of a gyroscope due to inertial frame dragging, close to the ergosphere of a ‘Draining Bathtub’ acoustic spacetime which has been studied extensively for acoustic Hawking radiation of phonons and also for ‘superresonance’. The formula is verified by embedding the two dimensional spatial (acoustic) geometry into a three dimensional one where the similarity with standard Lense-Thirring precession results within a strong gravity framework is well known. Prospects of experimental detection of this new ‘fixed-metric’ effect in acoustic geometries, are briefly discussed.The Lense-Thirring effect due to inertial frame dragging in a rotating spacetime is explored for the first time for a two-dimensional acoustic analogue black hole spacetime known as the ‘Draining Bathtub’. Quantum spin relaxation in interaction with phonons have been known in paramagnetic crystals to induce a spin for phonons which can precess around the orbital angular momentum. This may pave the way for observation of the acoustic analogue of Lense-Thirring precession in a laboratory setup, if realised in a BEC system. PubDate: 2017-11-15T12:31:06.341938-05: DOI: 10.1002/andp.201700231

Authors:Andriy E. Serebryannikov; Akhlesh Lakhtakia, Ekmel Ozbay Abstract: The characteristics of multiple cascaded metasurfaces comprising H-shaped, magnetostatically controllable, subwavelength terahertz (THz) resonators made of InAs were systematically investigated, using a commercial solver based on the finite-integration method, for the design of tunable filters. Three configurations of the biasing magnetostatic field were compared with each other as well as with the bias-free configuration for filtering of normally incident linearly polarized plane waves. A close study of only one metasurface was found sufficient to broadly determine the sensitivity to the direction of the magnetostatic field and the bandwidth of a stopband. Furthermore, the effects of metasurface geometry and biasing field can be considered separately for initial design purposes. All features in the transmittance spectra for the bias-free configuration that are related to the number of cascaded metasurfaces are also observed when the biasing magnetostatic field is applied. The coupling of adjacent metasurfaces in a cascade is strongly affected by the relative permittivity and the thickness of the spacer between the two metasurfaces. The spectral locations of stopbands scale with respect to the spacer's relative permittivity, the scaling rule being different from a classical one. The stopbands are redshifted when the spacer thickness is increased, with the redshift dependent on the polarization of the incident plane wave. Inter-metasurface coupling and inter-resonator coupling on the same metasurface affect the spectral location of a stopband in opposite ways. On-off type switching can be obtained by changing the orientation of magnetostatic field. The elucidated characteristics are expected to be important for not only filters but also other tunable THz devices.Metasurfaces are planar arrays of subwavelength resonators designed to elicit specific performance metrics. Design principles for single and cascaded metasurfaces comprising H-shaped resonators of InAs are extracted from several numerical studies, InAs being a magnetostatically tunable material in the terahertz spectral regime. Magnetostatic biasing, the substrate/spacer material, and resonators on the same and neighboring metasurfaces compete as well as cooperate to deliver tunable stopbands. PubDate: 2017-11-14T12:57:14.530082-05: DOI: 10.1002/andp.201700252

Authors:Wei-Ping Zhong; Milivoj R. Belić, Yiqi Zhang Abstract: By using the modified Snyder-Mitchell (MSM) model, which can describe the propagation of a paraxial beam in fractional dimensions (FDs), we find the exact "accessible soliton” solutions in the strongly nonlocal nonlinear media with a self-consistent parity-time (PT) symmetric complex potential. The exact solutions are constructed with the help of two special functions: the complex Gegenbauer and the generalized Laguerre polynomials in polar coordinates, parametrized by two nonnegative integer indices - the radial and azimuthal mode numbers (n,m), and the beam modulation depth. By the choice of different soliton parameters, the intensity and angular profiles display symmetric and asymmetric structures. We believe that it is important to explore the MSM model in FDs and PT-symmetric potentials, for a better understanding of nonlinear FD physical phenomena. Different physical systems in which the model might be of relevance are briefly discussed.Nonlinear nonlocal systems with PT symmetry and fractional dimension have come to the focus of researchers in various fields of physics. Such systems commonly appear in nonlinear optics, where the change in the refractive index appears as a potential in the Schrȍdinger equation, allowing for optical analogues of various quantum-mechanical phenomena. The authors study fraction-dimensional accessible soliton solutions of the modified Snyder-Mitchell model of strongly nonlocal nonlinear Schrȍdinger equation with a self-consistent PT-symmetric potential. The exact solutions are constructed with the help of Gegenbauer and Laguerre polynomials in polar coordinates, parametrized by two integer indices - the radial and azimuthal mode numbers. By the choice of different parameters, the intensity of solitons displays symmetric and asymmetric structures. PubDate: 2017-11-14T02:37:18.058034-05: DOI: 10.1002/andp.201700311

Authors:Jieci Wang; Jiliang Jing, Heng Fan Abstract: We study the behavior of monogamy deficit and monogamy asymmetry for Einstein-Podolsky-Rosen steering of Gaussian states under the influence of the Hawking effect. We demonstrate that the monogamy of quantum steering shows an extreme scenario in the curved spacetime: the first part of a tripartite system cannot individually steer two other parties, but it can steer the collectivity of the remaining two parties. We also find that the monogamy deficit of Gaussian steering, a quantifier of genuine tripartite steering, are generated due to the influence of the Hawking thermal bath. Our results elucidate the structure of quantum steering in tripartite quantum systems in curved spacetime.The steering monogamy deficit and the steering monogamy asymmetry are defined. The monog-amy of quantum steering shows an extreme scenario in the curved spacetime: the first part of a tripartite system cannot individually steer two other parties, but it can steer the collective of the remaining two parties. The maximizing condition for the monogamy asymmetry is exactly the transition point of the bipartite steering asymmetry. PubDate: 2017-11-14T02:36:42.127999-05: DOI: 10.1002/andp.201700261

Authors:Taiming Sun; Zhixiang Deng, Jiabing Sheng, Zhiyong Chen, Weihua Zhu, Wei Guo, Xinlin Wang Abstract: We studied numerically the enhanced optical transmission (EOT) through periodic subwavelength circular-sharp hole arrays in metallic films with different edge sharp distribution features of unit structures. Detailed studies indicate that the unit structure edge sharp distribution features strongly influence the surface plasmons (SPs). These results demonstrate that the number of edge sharp activated the localized surface plamons (LSP) resonance on the unit structure is changed by rotating the polarization of the incident light, leading to change the infrared transmittance of the array. Moreover, a compact plasmonic switch via periodic circular-sharp hole arrays based on the dependence of SPs on unit structural edge sharp distributions is proposed. The finding provides a new idea for designing plasmonics devices, and expands the application range of metal micro-nano structure in the field of optical communications and information processing.In this study, the enhanced optical transmission (EOT) of circular-sharps shaped hole arrays have been investigated numerically. It is found that the edge sharp distributions have influence the transmission of light mainly by changing the LSP resonance strength on edge sharp. Base on this, a compact plasmonic switch via periodic circular-sharp hole arrays is proposed. It is turned “on” and “off” state by changing the direction of polarization of the light. This research expand the application range of metal micro-nano structure in the field of optical communications and information processing. PubDate: 2017-11-13T06:00:11.938797-05: DOI: 10.1002/andp.201700299

Authors:Patrycja Łydżba; Janusz Jacak Abstract: We introduce a method that allows the disclosure of correlations between particle positions in an arbitrary many-body system. The method is based on a well-known simulated annealing algorithm and the proposed artificial distribution technique. Additionally, we investigate correlations in quantum Hall liquids (we consider many-body wave functions that have been recently determined via the cyclotron subgroup model) and present three-dimensional plots of configuration probability distributions that have been established from numerical simulations. We demonstrate that the preferred simultaneous positions of particles (configurations of positions, which correspond to large values of a system's probability distribution, ΨN 2) tend to form complicated geometric structures, which are equivalent to classical Wigner crystals only for Laughlin states. Furthermore, we claim that quantum Hall liquids attributed to non-Laughlin fillings are correlated on subdomains rather than on a whole particle domain (due to a quantizing magnetic field, which modifies the topology of a system's dynamics). Finally, we characterize Hall-like internal orders in terms of statistical correlations (one-dimensional unitary representations of cyclotron subgroups). Our conclusions concerning the stability of many-body states agree with transport measurements and various numerical studies.A numerical procedure which allows to disclose correlations between particle positions in many-body systems is proposed. It can identify the most probable configuration of wave function’s arguments and the configuration probability distribution. In the paper, the numerical procedure is implemented to describe internal correlations of quantum Hall liquids. Differences between Laughlin and Jain liquids are revealed and explained. Investigated many-body wave functions were deduced from the topological approach. PubDate: 2017-11-13T05:59:41.06973-05:0 DOI: 10.1002/andp.201700221

Authors:Jinjin Jin; Xiaohu Zhang, Ping Gao, Jun Luo, Zuojun Zhang, Xiong Li, Xiaoliang Ma, Mingbo Pu, Xiangang Luo Abstract: Ascribing to the properties of two dimensional parallel focusing and imaging, low propagation loss, integration and miniaturization, microlens array has been widely used in imaging, optical communication, organic light emitting devices, adaptive optics, photolithography, biomedical and other applications. However, the existing traditional microlens array suffers from difficulty in fabrication, large-thickness, curved surface, non-uniformity of light spots, or requirement of additional discrete components to control the microlens. Herein, a planar microlens array is experimentally demonstrated based on the geometric metasurface. The single microlens is composed of space-variant subwavelength metallic gratings with high polarization conversion efficiency and thus exhibits gradient phase distribution. The focused spot diameter of 22.5 μm with radius of 350 μm, focal length of 1 cm and the light spots intensity uniformity of 0.9885 (standard deviation 0.0115) at the focal plane are obtained. Moreover, the broadband property of microlens array is also confirmed. The novel design strategy for microlens array would facilitate the miniaturization of optical devices and be easily integrated in the optical interconnected devices.The microlens array is realized by the ultrathin metasurface, which posses numerous merits including ultrathin (≈λ/10), flat and flexible. Experiment results indicate the uniformity of the focus spots generated by the microlens is high up to 0.9885. This approach may facilitate the applications of the metasurface and advance the high integration of the parallel optical systems. PubDate: 2017-11-13T05:57:27.707631-05: DOI: 10.1002/andp.201700326

Authors:Emanuele Verrelli; Irini Michelakaki, Nikos Boukos, Georgios Kyriakou, Dimitris Tsoukalas Abstract: In this work is presented the growth model for Au films grown on a carbon substrate at room temperature by using as building blocks Au nanoparticles (NPs) with 1.4 nm mean size generated via remote cluster beam synthesis and soft landing on the substrate. The key results highlighted in this work are that 1) the deposited nanoparticles coalesce at substrate level in such a way that the film growth is 3D, 2) newly formed nanoparticles at substrate level are predominantly magic number clusters and 3) coalescensce takes place as soon as two neighboring nanopartciles come closer than a critical distance. The film growth was investigated by TEM as a function of Au load, in the range 0–1.2 μg/cm2. Two distinct regimes are identified: the “landing regime” and the “coalescence regime”. During the latter the film growth is 3D with a dynamic scaling exponent z of 2.13. Particular attention was devoted to the study of the evolution of the NP population from the moment they are generated with the cluster beam generator to the moment they land on the substrate and coalesce with other NPs. Our results show that 1) the NPs generated by the cluster beam are heterogeneous in size and are made by more than 95% by Au Magic numbers, mainly Au20 and Au55 and 2) kinetic processes (coalescence) at substrate level is capable of producing NPs populations made of larger Au magic numbers containing up to several thousands of Au atoms. Experimental and simulation results provide insight into the coalescence mechanism and provide strong evidence that the NPs coalesce when the nearest neighbor distance is below a critical mark. The critical distance is at its minimum 0.4-0.5 nm and it is still unclear whether it is constant or not although the best matching simulation results seem to point to a superlinear dependence from the NP size difference between two neighboring candidate coalescing NPs. The coalescence phenomenon investigated in this work pinpoints the unique self-organization properties of these small Au NPs in creating films with a stable edge-to-edge mean nearest neighbor distance of the order of 1.4 nm.Au films grown by depositing sub-2m Au nanoparticles show that 1) the deposited nanoparticles coalesce at substrate level in such a way that the film growth is 3D, 2) newly formed nanoparticles at substrate level are predominantly magic number clusters and 3) coalescensce takes place as soon as two neighboring nanopartciles come closer than a critical distance. A range of gold magic numbers have been identified, some created directly by the cluster beam generator (e.g. Au55) and others formed through kinetic processes (coalescence) taking place at substrate level upon NP deposition (e.g. Au561). PubDate: 2017-11-13T05:56:59.51565-05:0 DOI: 10.1002/andp.201700256

Authors:Mario Junior Neves; Jose A. Helaÿel-Neto Abstract: The standard electroweak interaction is here re-assessed to accommodate two different situations in Particle Physics. The first one is a Z′-model at the TeV-scale physics. The second one tackles the recent discussion of a possible fifth force mediated by a 17-MeV X-boson associated with an electron-positron emission in the transition of an excited 8-Beryllium to its ground state. The anomaly-free model that provides these two scenarios is based on an SUL(2)×UR(1)J×U(1)K-symmetry. It yields a new massive neutral boson, an exotic massive neutral fermion, right-neutrinos and an additional neutral Higgs particle, which stems from a supplementary Higgs field, introduced along with the usual Higgs doublet responsible for the electroweak breaking and the masses of W± and Z0. Yukawa interactions of the two scalars generate the masses of the Standard Model leptons, neutrinos and a new exotic fermion of the model. The vacuum expectation values of the Higgses fix up two independent energy scales. One of them is the well-confirmed electroweak scale, 246 GeV, whereas the other one is set up by adopting an experimental estimate for the Z′-mass.The model sets out to study an extension of the standard electroweak model with a spontaneous symmetry breaking pattern that yields scenarios with a heavy or a light gauge boson. The introduction of a new exotic fermionic particle, allowed by the symmetries, connects the known barionic matter with a possible dark matter sector through the cascade effects involving the heavy or the light boson decays. The model may be of interest to describe the phenomenology of new particles including also the dark sector in an energy scale above or below the Standard Model scale. PubDate: 2017-11-13T05:55:59.263488-05: DOI: 10.1002/andp.201700112

Authors:Joachim Wosnitza Abstract: In this short review, the recently found experimental evidence that Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) states are realized in quasi-two-dimensional (2D) organic superconductors is reported. At low temperatures and when a high magnetic field is aligned parallel to the conducting organic layers, an upturn of the upper critical field much beyond the Pauli limit is observed, as proven by thermodynamic measurements. Under certain conditions, a second thermodynamic transition emerges inside the FFLO state. Nuclear magnetic resonance (NMR) work has added strong microscopic support for the realization of the FFLO state. The NMR spectra in the FFLO phase can very well be explained by a nonuniform one-dimensionally modulated superconducting order parameter. All these features, appearing only in a very narrow angular region close to parallel-field orientation, give robust evidence for the realization of the FFLO state in organic superconductors.High magnetic fields favor parallel spins, whereas singlet superconducting Cooper pairs have antiparallel spins. As predicted already 1964 by Fulde and Ferrell and, independently, by Larkin and Ovchinnikov, a compromise superconducting state may still exist even beyond the Pauli limit with spatially separated superconducting (orange Cooper pairs) and magnetically ordered regions (blue). Here, the author reviews the clear evidence for these so-called FFLO states found in layered organic superconductors. PubDate: 2017-11-03T01:31:01.324302-05: DOI: 10.1002/andp.201700282

Authors:S. H. Hendi; N. Riazi, S. Panahiyan Abstract: The content of this paper includes studying holographical and thermodynamical aspects of dyonic black holes in the presence of massive gravity. For the first part of paper, thermodynamical properties of the bulk which includes black holes are studied and the main focus is on critical behavior. It will be shown that the existence of massive gravitons introduces remnant for temperature after evaporation of black holes, van der Waals phase transition for non-spherical black holes and etc. The consistency of different thermodynamical approaches toward critical behavior of the black holes is presented and the physical properties near the region of thermal instability are given. Next part of the paper studies holographical aspects of the boundary theory. Magnetization and susceptibility of the boundary are extracted and the conditions for having diamagnetic and paramagnetic behaviors are investigated. It will be shown that generalization to massive gravity results into the existence of diamagnetic/paramagnetic phases in phase structure of the hyperbolic and horizon flat of boundary conformal field theory.Recent LIGO report of detecting the gravitational waves provided a deep insight to general relativity and existence of massive gravitons. Also, phase transition of black holes in analogy to the van der Waals gas/liquid system, opens a new theoretical avenue to study black hole thermodynamics. The effects of graviton's mass on thermodynamical structure of dyonic black holes and holographic properties of the corresponding conformal field theory are explored. PubDate: 2017-10-16T04:26:15.083353-05: DOI: 10.1002/andp.201700211