Generating synthetic magnetism via Floquet engineering auxiliary qubits in phonon-cavity-based lattice

Abstract

Gauge magnetic fields have a close relation to breaking time-reversal symmetry in condensed matter.In the presence of the gauge fields, we might observe nonreciprocal and topological transport. Inspired by these, there is a growing effort to realize exotic transport phenomena in optical and acoustic systems. However, due to charge neutrality, realizing analog magnetic flux for phonons in nanoscale systems is still challenging in both theoretical and experimental studies. Here we propose a novel mechanism to generate synthetic magnetic field for phonon lattice by Floquet engineering auxiliary qubits. We find that, a longitudinal Floquet drive on the qubit will produce a resonant coupling between two detuned acoustic cavities. Specially, the phase encoded into the longitudinal drive can exactly be transformed into the phonon-phonon hopping. Our proposal is general and can be realized in various types of artificial hybrid quantum systems. Moreover, by taking surface-acoustic-wave (SAW) cavities for example, we propose how to generate synthetic magnetic flux for phonon transport. In the presence of synthetic magnetic flux, the time-reversal symmetry will be broken, which allows one to realize the circulator transport and analog Aharonov-Bohm effects for acoustic waves. Last, we demonstrate that our proposal can be scaled to simulate topological states of matter in quantum acoustodynamics system.In recent years, manipulating acoustic waves at a single-phonon level has drawn a lot of attention [28], and the quantum acoustodynamics (QAD) based on piezoelectric surface acoustic waves (SAW) has emerged as a versatile platform to explore quantum features of acoustic waves [29][30][31][32][33][34][35][36]. Unlike localized mechanical oscillations [37][38][39], the piezoelectric surface is much larger compared with the acoustic wavelength. Therefore, the phonons are itinerant on the material surface and in the form of propagating waves [31]. To control the quantized motions effectively, the SAW cavities are often combined with other systems, for example, with superconducting qubits or color centers, to form as hybrid quantum systems [40]. Analog to quantum controls with photons, many acoustic devices, such as circulators, switches and routers, are also needed for generating, controlling, and detecting SAW phonons in QAD experiment [10,35,[41][42][43][44][45][46][47]. However, it is still challenging to realize these nonreciprocal acoustic quantum devices in the artificial nano-and micro-scale SAW systems [27,48].By applying an external time periodic drive on a static system, the effective Hamiltonian of the whole system for the longtime evolution can be tailed freely, which allows one to observe topological band properties. This approach is referred as Floquet engineering [49][50][51], and has been exploited to simulate the topological toy models such as Haldane and Harper-Hofstadter lattices in artificial systems [21]. Inspired by these studies, we propose a novel method to realize synthetic magnetism in the phonon systems ...

Chiral quantum network with giant atoms

“…The decoupling mechanism between the giant atom and modes in one propagating direction is similar to realize chiral quantum phenomena via generating synthetic gauge fields in discretized lattice model [18,[70][71][72][73]. Different from those studies, our proposal is based on giant atom effects in SQC platforms, and especially feasible for conventional continuous waveguides which are more robust to disorder noise than spin-chain channels.…”

Complex decoherence-free interactions between giant atoms

“…( 15) and ( 16) that the modulation phase θ is encoded into the DFI between atoms A and B, mimicking a synthetic magnetic flux for photons transferring in between. Although the coupling phase θ can be gauged away for such a two-atom model (thus it has no particular interest in this case), it can significantly affect the dynamics of the system when a third atom is introduced to form a closed-loop trimer [22,42,45,46], as will be shown below.…”

Unconventional Quantum Electrodynamics with Hofstadter-Ladder Waveguide

“…In this work, we discuss QED phenomena in a setup composed by quantum emitters and a Hofstadter-ladder waveguide. Different from previous studies based on lattice environment with synthetic gauge fields [56][57][58][59], here we mainly focus on unconventional QED phenomena induced by the spin-orbit coupling. First, we assume that the emitter is of small atom form which frequency is resonant with the lower energy band.…”