First page: 033007 Abstract: The renormalization group (RG) is a class of theoretical techniques used to explain the collective
physics of interacting, many-body systems. It has been suggested that the RG formalism may be useful
in finding and interpreting emergent low-dimensional structure in complex systems outside of the
traditional physics context, such as in biology or computer science. In such contexts, one common
dimensionality-reduction framework already in use is information bottleneck (IB), in which the goal
is to compress an ‘input’ signal X while maximizing its mutual information with some stochastic
‘relevance’ variable Y . IB has been applied in the vertebrate and invertebrate processing systems
to characterize optimal encoding of the future motion of the external world. Other recent work has
shown that the RG scheme for the dimer model could be ‘discovered’ by a neural network attempting to
solve an IB-like problem. This manuscript explores whether IB and any existing formulation... Citation: New Journal of Physics PubDate: 2022-03-09T00:00:00Z DOI: 10.1088/1367-2630/ac395d Issue No:Vol. 24, No. 3 (2022)

First page: 033008 Abstract: We consider a nanoelectromechanical weak link composed of a carbon nanotube suspended above a trench
in a normal metal electrode and positioned in a gap between two superconducting leads. The nanotube
is treated as a movable single-level quantum dot (QD) in which the position-dependent
superconducting order parameter is induced as a result of Cooper pair tunneling. We show that in
such a system, self-sustained bending vibrations can emerge if a bias voltage is applied between
normal and superconducting electrodes. The occurrence of this effect crucially depends on the
direction of the bias voltage and the relative position of the QD level. We also demonstrate that
the nanotube vibrations strongly affect the dc current through the system, a characteristic that can
be used for the direct experimental observation of the predicted phenomenon. Citation: New Journal of Physics PubDate: 2022-03-09T00:00:00Z DOI: 10.1088/1367-2630/ac5758 Issue No:Vol. 24, No. 3 (2022)

First page: 033010 Abstract: In this work, we investigate the topological phase transitions and corresponding transport
properties in zigzag stanene nanoribbon with different magnetism. The results show that the
off-resonant circularly polarized (ORCP) light may induce anisotropic chiral edge state with a
magnetic phase transition from antiferromagnetic state to nonmagnetic state. In combination with the
ORCP light and electric field, the 100% spin-polarized edge state can be induced with some magnetic
orders. The finite-size effect is also an important factor for the magnetic phase transitions, which
in turn induces topological phase transitions from the band insulator to topological phases. By
constructing the topological-insulator junctions with some topological edge states, we further study
the Fabry–Perot resonant, where multiple reflection edge states cause strong current loops. By
modulating the ORCP and electric field, the system can also be regarded as a switcher, to control
the charge current or s... Citation: New Journal of Physics PubDate: 2022-03-10T00:00:00Z DOI: 10.1088/1367-2630/ac4009 Issue No:Vol. 24, No. 3 (2022)

First page: 033011 Abstract: We study electron acceleration in a plasma wakefield under the influence of the radiation-reaction
force caused by the transverse betatron oscillations of the electron in the wakefield. Both the
classical and the strong quantum-electrodynamic (QED) limits of the continuous radiation reaction
are considered. For the constant accelerating force, we show that the amplitude of the oscillations
of the QED parameter χ in the radiation-dominated regime reaches an equilibrium value determined
only by the magnitude of the accelerating field, while the averaged over betatron oscillations
radiation reaction force saturates at a value smaller than the accelerating force and thus is
incapable of stopping acceleration. We find the parameters of the electron bunch and the plasma
accelerator for which reaching such a regime is possible. We also study effects of the dephasing and
the corresponding change of the accelerating force over the course of acceleration and conclude that
the radia... Citation: New Journal of Physics PubDate: 2022-03-10T00:00:00Z DOI: 10.1088/1367-2630/ac53b9 Issue No:Vol. 24, No. 3 (2022)

First page: 033012 Abstract: We introduce and analyze an open quantum generalization of the q-state Potts-Hopfield neural network
(NN), which is an associative memory model based on multi-level classical spins. The dynamics of
this many-body system is formulated in terms of a Markovian master equation of Lindblad type, which
allows to incorporate both probabilistic classical and coherent quantum processes on an equal
footing. By employing a mean field description we investigate how classical fluctuations due to
temperature and quantum fluctuations effectuated by coherent spin rotations affect the ability of
the network to retrieve stored memory patterns. We construct the corresponding phase diagram, which
in the low temperature regime displays pattern retrieval in analogy to the classical Potts-Hopfield
NN. When increasing quantum fluctuations, however, a limit cycle phase emerges, which has no
classical counterpart. This shows that quantum effects can qualitatively alter the structure of the
stationary sta... Citation: New Journal of Physics PubDate: 2022-03-10T00:00:00Z DOI: 10.1088/1367-2630/ac5490 Issue No:Vol. 24, No. 3 (2022)

First page: 033013 Abstract: Various scientific and industrial researches such as spectroscopy and advanced nano-technologies
have been demanding high flux and fully coherent extreme ultraviolet (EUV) and x-ray radiation.
These demands can be commendably satisfied with a MHz-level repetition-rate seeded free-electron
laser (FEL). Dictated by the seed laser system, seeded FELs have faced obstacles for the realization
of MHz repetition rate. Reducing the required peak power of an external coherent seed laser can
effectively increase the repetition rate of a seeded FEL. This paper presents a novel technique that
employs a long modulator as a carrier for laser amplification and electron modulation, which is
quite different from nominal seeded FELs. Applications of the proposed technique into high-gain
harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are investigated. Simulation
results demonstrate that seed laser power is reduced by about three orders of magnitude and the FEL
radiation pos... Citation: New Journal of Physics PubDate: 2022-03-10T00:00:00Z DOI: 10.1088/1367-2630/ac5492 Issue No:Vol. 24, No. 3 (2022)

First page: 033014 Abstract: Diffraction in time manifests itself as the appearance of probability-density fringes when a matter
wave passes through an opaque screen with abrupt temporal variations of transmission properties.
Here we analytically describe the phase-space structure of diffraction-in-time fringes for a class
of smooth time gratings. More precisely, we obtain an analytic expression for the Husimi
distribution representing the state of the system in the case of time gratings comprising a
succession of Lorentzian-like slits. In particular, for a double-slit scenario, we derive a simple
and intuitive expression that accurately captures the position of interference fringes in phase
space. Citation: New Journal of Physics PubDate: 2022-03-11T00:00:00Z DOI: 10.1088/1367-2630/ac5563 Issue No:Vol. 24, No. 3 (2022)

First page: 033015 Abstract: Protection of gauge invariance in experimental realizations of lattice gauge theories based on
energy-penalty schemes has recently stimulated impressive efforts both theoretically and in setups
of quantum synthetic matter. A major challenge is the reliability of such schemes in non-abelian
gauge theories where local conservation laws do not commute. Here, we show through exact
diagonalization (ED) that non-abelian gauge invariance can be reliably controlled using
gauge-protection terms that energetically stabilize the target gauge sector in Hilbert space,
suppressing gauge violations due to unitary gauge-breaking errors. We present analytic arguments
that predict a volume-independent protection strength V , which when sufficiently large leads to the
emergence of an adjusted gauge theory with the same local gauge symmetry up to least a timescale
##IMG## [http://ej.iop.org/images/1367-2630/24/3/033015/njpac5564ieqn1...] {$\propto
\sqrt{V/{V}_{0}^{3}}$} Citation: New Journal of Physics PubDate: 2022-03-11T00:00:00Z DOI: 10.1088/1367-2630/ac5564 Issue No:Vol. 24, No. 3 (2022)

First page: 035001 Abstract: We study heat rectification through quantum dots in the Coulomb blockade regime using a master
equation approach. We consider both cases of two-terminal and four-terminal devices. In the
two-terminal configuration, we analyze the case of a single quantum dot with either a
doubly-degenerate level or two non-degenerate levels. In the sequential tunneling regime we analyze
the behaviour of heat currents and rectification as functions of the position of the energy levels
and of the temperature bias. In particular, we derive an upper bound for rectification in the
closed-circuit setup with the doubly-degenerate level. We also prove the absence of a bound for the
case of two non-degenerate levels and identify the ideal system parameters to achieve nearly perfect
rectification. The second part of the paper deals with the effect of second-order cotunneling
contributions, including both elastic and inelastic processes. In all cases we find that there
exists ranges of values of parameters... Citation: New Journal of Physics PubDate: 2022-03-10T00:00:00Z DOI: 10.1088/1367-2630/ac53b8 Issue No:Vol. 24, No. 3 (2022)

First page: 035002 Abstract: Tailoring optically resonant features in dielectric metasurfaces unveils a robust scheme to control
electromagnetic near fields of light and thus to boost the nanoscale nonlinear light–matter
interactions. Membrane metasurfaces offer unique possibilities for supporting multipolar resonances
and meanwhile maintaining high mode volume for enhancing nonlinear frequency conversion. Here we
design a silicon membrane metasurface consisting of dimer airy holes, as a versatile platform for
generating four-wave mixing (FWM). We show that such a metasurface exhibits a multi-resonant
feature, including a quasi bound state in the continuum (BIC) generated by the collective toroidal
dipole mode excited in the designed subdiffractive periodic system. We show that via employing the
BIC mode in the short-wave infrared (SWIR), together with other resonant enhanced electric near
fields in the near-infrared (NIR) region, simultaneously, one can convert invisible SWIR light to
visible light radiati... Citation: New Journal of Physics PubDate: 2022-03-11T00:00:00Z DOI: 10.1088/1367-2630/ac55b2 Issue No:Vol. 24, No. 3 (2022)