We study the effects of position passive and active cavities on spontaneous parity-time- ($\mathcal{PT}$-) symmetry-breaking behavior in a non-Hermitian coupled-cavity-array model. analyze discuss energy eigenvalue spectra $\mathcal{PT}$ symmetry topologically trivial nontrivial regimes under three different cases detail; that is, are located at, respectively, two end positions, second penultimate each coupled-cavity array. The odevity number is further considered to check terms applied...

A scheme is proposed to enhance the photon blockade effect in a hybrid optomechanical system with $\mathrm{\ensuremath{\Lambda}}$-type atom driven by microwave. Through analyzing conventional and unconventional mechanisms, we find that enhanced can be attributed two aspects: (i) The nonresonant coupled reconstructs anharmonic eigenenergy spectrum (ii) microwave driving field promotes destructive quantum interference for two-photon excitation. By means of joint enhancement effect, perfect...

We show how to implement the various kinds of topological routers via introducing specific long-range hopping in one-dimensional modulated Su-Schrieffer-Heeger chain. find that with amplitudes identical those intercell between first site and other odd sites holds a distinctive channel (gap state), by which particle initially prepared at last can appear all even approximately equal probabilities. This extraordinary performance indicates that, from perspective treating as input port output...

Topological pumping has numerous applications in quantum information processing, e.g., the spatial entanglement distribution of two correlated particles via disordered bulk channel modulated Rice-Mele model [Phys. Rev. A 101, 052323 (2020)]. This actually indicates that, Thouless assisted by disorder, particle initially prepared at middle site can be pumped towards two-end sites with approximately equal probability, which exhibits latent possibility to implement topological split-flow...

Abstract A potential application, quantum diode based on the adiabatic pumping between two specific left and right edge modes, is explored in a one-dimensional cyclically modulated circuit electrodynamic dimer mapped successfully to paradigmatic Su-Schrieffer-Heeger model. The characterized by presence of nonreciprocity transport, which describes one-way transfer excitations at both boundary resonators lattice. We find that quality defined fidelity can be improved increasing modulation...

We propose a novel scheme to simulate Z2 topological insulators via one-dimensional (1D) cavity optomechanical cells array. The direct mapping between 1D array and 2D quantum spin Hall (QSH) system can be achieved by using diagonalization dimensional reduction methods. show that the features of present model captured generalized Harper equation with an additional SU(2) guage structure. Interestingly, pumping effective photon-phonon bosons naturally derived after scanning periodic parameter,...

Considering the strong built-in electric field caused by polarization in wurtzite nitride heterostructures, energy levels and wave functions of two-dimensional electrons AlyGa1−yN back-barrier Al2O3/InxAl1−xN/GaN heterostructures are calculated using finite element difference method. The dispersion relations electrostatic potentials optical phonons obtained transfer matrix electron mobility under phonon scattering is studied based on theory Lei–Ting force balance equation. influences back...

We propose a novel scheme to simulate Z_2 topological insulators via one-dimensional (1D) cavity optomechanical cells array. The direct mapping between 1D array and 2D quantum spin Hall (QSH) system can be achieved by using diagonalization dimensional reduction methods. show that the features of present model captured generalized Harper equation with an additional SU(2) guage structure. Interestingly, pumping effective photon-phonon bosons naturally derived after scanning periodic parameter,...

We investigate the localized photonic states and dynamic process in one-dimensional nonreciprocal coupled Su-Schrieffer-Heeger chain. Through numerical calculation of energy eigenvalue spectrum state distributions system, we find that different with special eigenvalues can be induced by coupling, such as zero-energy edge states, interface bound pure imaginary eigenvalues. Moreover, analyze non-Hermitian system. Interestingly, it is shown coupling has an evident gathering effect on photons,...

Abstract The topological properties of a generalized non‐Hermitian Su–Schrieffer–Heeger model are investigated and it is demonstrated that the phase transition skin effect can be induced by intra‐cell asymmetric coupling under open boundary conditions. Through investigating calculating winding number with Brillouin zone theory, found present system has an exact bulk‐boundary correspondence relationship. Meanwhile, used to characterize determine boundary, not completely strength. By means...

Quantum transport in a one-dimensional (1D) quasiperiodic lattice with mobility edges is explored. We first investigate the adiabatic pumping between left and right edge modes by resorting to two edge-bulk-edge channels demonstrate that success or failure of depends on whether corresponding bulk subchannel undergoes localization-delocalization transition. Compared paradigmatic Aubry-Andr\'e (AA) model, introduction triggers an opposite outcome for successful channels, showing discrepancy...

We propose two kinds of distinguishing parameter regimes to induce a topological Su-Schrieffer-Heeger (SSH) phase in one-dimensional (1D) multiresonator cavity optomechanical system via modulation the frequencies both fields and resonators. The introduction frequency modulations allows us eliminate Stokes heating process for mapping tight-binding Hamiltonian without usual rotating-wave approximation, which is totally different from traditional model. find that can be mapped into SSH...

Assisted by a quantum dot-microcavity coupled system, we propose an entanglement concentration scheme for concentrating two unknown partially entangled three-photon W states into maximally state based on spin selective photon reflection from the cavity and interference of polarized photons. In scheme, three parties, say Alice, Bob, Charlie in different distant locations can successfully share with high probability success local operations performed Alice classical communication. We calculate...

Abstract Non-Hermitian Hamiltonians with anti- <?CDATA $\mathcal{PT}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mi mathvariant="script">PT</mml:mi> </mml:math> symmetry show distinct discrepancies compared to -symmetric systems. Here we investigate the non-Hermitian Su–Schrieffer–Heeger (SSH) model and reveal interplay between different topological phases, in which is triggered by introducing real chemical potential imaginary...

Abstract A scheme to investigate the topological properties in a two‐leg Kitaev ladder system composed of two chains is proposed. In case identical chains, it found that interchain hopping amplitude plays significant role separation energy spectrum and inducing topologically nontrivial phase, while pairing strength only affects size gap. Moreover, another situation consists non‐identical also investigated corresponding phase diagram calculated. It pairs degenerate nonzero edge modes will,...

We investigate the quantum walks of a single particle in one-dimensional periodically kicked circuit electrodynamics lattice. It is found that dynamic process walker affected by strength incommensurate potentials and driven periods system. calculate mean square displacement to illustrate properties walks, which shows localized presents zero power-law index distribution. By calculating information entropy, we find next-nearest-neighbor interactions have remarkable deviation effects on make...

Based on the principle of density matrix and finite element method, interband optical absorption between electron hole has been investigated in a wurtzite [Formula: see text] spherical core–shell quantum dot (CSQD) including strong built-in electric field (BEF). We have studied effects size ternary mixed crystal coefficients (ACs) refraction index changes (RICs). The results indicate that peaks ACs RICs decrease rapidly, show redshift with increase component text]. It is also found reduce...

The linear and nonlinear optical absorption coefficients (ACs) refraction index changes (RICs) of 1s–1p, 1p–1d, 1f–1d transitions are investigated in a wurtzite In x Ga 1 – N/GaN core–shell quantum dot (CSQD) with donor impurity by using density matrix approach. effects built-in electric field (BEF), ternary mixed crystal (TMC), impurity, CSQD size studied detail. finite element method is used to calculate the ground excited energy state wave function. results reveal that BEF has great...