Searcharxiv⌕ Search

arXiv subjects

Yao-Tong Chen

Publications and source records attributed to Yao-Tong Chen.

9 recordsLinked to original sources
arXiv2026

Spinning giant optomechanical cavity with nonreciprocal self-interference

We study a spinning optomechanical cavity that is coupled to a meandering waveguide at multiple spatially separated points, forming a giant-cavity configuration. The resulting self-interference makes the effective optical driving, linewidth, and frequency shift strongly dependent on the propagation phase in the waveguide, while the rotation-induced Sagnac-Fizeau shift causes the clockwise (CW) and counterclockwise (CCW) cavity modes to experience distinct interference phases. Under single-tone driving, this mechanism enables phase-controlled phonon cooling and, in the presence of cavity rotation, nonreciprocal cooling, with one propagation direction approaching the mechanical ground-state regime while the opposite direction remains less efficiently cooled. Under two-tone driving, the same interference mechanism engineers a squeezed reservoir for the mechanical mode, producing steady-state squeezing that likewise becomes nonreciprocal under cavity rotation. These results establish multi-point self-interference as a versatile mechanism for phase-controlled optomechanical reservoir engineering and show that, when combined with cavity rotation, it provides a route to nonreciprocal quantum effects.

quant-ph↗
arXiv2023

Single-photon manipulations based on optically-controlled chiral couplings in waveguide structures of Rydberg giant atoms

Two interacting Rydberg atoms coupled to a waveguide realize a giant-atom platform that exhibits the controllable (phase-dependent) chirality where the direction of nonreciprocal photon scattering can be switched on demand, e.g., by the geometrical tuning of an external driving field. At variance with previous chiral setups, the simplified approach of our proposed platform arises from an optical implementation of the local phase difference between two coupling points of the Rydberg giant atom. Furthermore, employing two or more driving fields, this platform could also be used as a frequency converter with its efficiency exhibiting a strong asymmetry and being significantly enhanced via the chiral couplings. Our results suggest an extendable giant-atom platform that is both innovative and promising for chiral quantum optics and tunable frequency conversion in the optical domain.

quant-ph↗
arXiv2023

Decay dynamics of a giant atom in a structured bath with broken time-reversal symmetry

We study in this paper the decay dynamics of a two-level giant atom, which is coupled to a quasi-one-dimensional sawtooth lattice exposed to uniform synthetic magnetic fluxes. In the case where the two sublattices have a large detuning, the giant atom is effectively coupled to a single-band structured bath with flux-controlled energy band and time-reversal symmetry. This feature significantly affects the decay dynamics of the giant atom as well as the propagation of the emitted photon. In particular, the giant atom can exhibit chiral spontaneous emission and allow for nonreciprocal delayed light, which are however unattainable by coupling a small atom to this lattice. Giant atoms with different frequencies can be designed to emit photons towards different directions and with different group velocities. Our results pave the way towards engineering quantum networks and manipulating giant-atom interference effects.

quant-ph↗
arXiv2023

Giant-Atom Effects on Population and Entanglement Dynamics of Rydberg Atoms

Giant atoms are attracting interest as an emerging paradigm in the quantum optics of engineered waveguides. Here we propose to realize a synthetic giant atom working in the optical regime starting from a pair of interacting Rydberg atoms driven by a coherent field and coupled to a photonic crystal waveguide. Giant-atom effects can be observed as a phase-dependent decay of the double Rydberg excitation during the initial evolution of this atomic pair while (internal) atomic entanglement is exhibited at later times. Such an intriguing entanglement onset occurs in the presence of intrinsic atomic decay toward non-guided vacuum modes and is accompanied by an anti-bunching correlation of the emitted photons. Our findings may be relevant to quantum information processing, besides broadening the giant-atom waveguide physics with optically driven natural atoms.

quant-ph↗
arXiv2023

Nonreciprocal and chiral single-photon scattering for giant atoms

Quantum optics with giant atoms has provided a new paradigm to study photon scatterings. In this work, we investigate the nontrivial single-photon scattering properties of giant atoms being an effective platform to realize nonreciprocal and chiral quantum optics. For two-level giant atoms, we identify the condition for nonreciprocal transmission: the external atomic dissipation is further required other than the breaking of time-reversal symmetry by local coupling phases. Especially, in the non-Markovian regime, unconventional revival peaks periodically appear in the reflection spectrum. To explore more interesting scattering behaviors, we extend the two-level giant-atom system to Δ-type and {\nabla}-type three-level giant atoms coupled to double waveguides with different physical mechanisms to realize nonreciprocal and chiral scatterings. Our proposed giant-atom structures have potential applications of high-efficiency targeted routers that can transport single photons to any desired port deterministically and circulators that can transport single photons between four ports in a cyclic way.

quant-ph↗
arXiv2023

Perfect Transfer of enhanced entanglement and asymmetric steering in a cavity magnomechanical system

We propose a hybrid cavity magnomechanical system to realize and transfer the bipartite entanglements and Einstein-Podolsky-Rosen (EPR) steerings between magnons, photons, and phonons in the regime of stability of the system. As a parity-time-symmetric-like structure exhibiting the natural magnetostrictive magnon-phonon interaction, our passive-active cavity system can be explored to enhance the robust distant quantum entanglement and generate the relatively obvious asymmetric (even directional) EPR steering that is useful for the task with the highly asymmetric trusts of the bidirectional local measurements between two entangled states. It is of great interest that, based on such a tunable magnomechanical system, the perfect transfer between near and distant entanglements and steerings of different mode pairs is realized by adjusting the coupling parameters; in particular, we propose a perfect transfer scheme of steerings. These transferring processes suggest indeed an alternative method for quantum information storage and manipulation. In addition, the entanglements and steerings can also be exchanged between different mode pairs by adjusting the detunings between different modes. This work may provide a potential platform for distant and asymmetric quantum modulation.

quant-ph↗
arXiv2022

Giant atoms with time-dependent couplings

We study the decay dynamics of a two-level giant atom that is coupled to a waveguide with time-dependent coupling strengths. In the non-Markovian regime where the retardation effect cannot be ignored, we show that the dynamics of the atom depends on the atom-waveguide coupling strengths at an earlier time. This allows one to tailor the decay dynamics of the giant atom and even realize a stationary population revival with appropriate coupling modulations. Moreover, we demonstrate the possibility of simulating the quantum Zeno and quantum anti-Zeno effects in the giant-atom model with periodic coupling quenches. These results have potential applications in quantum information processing and quantum network engineering.

quant-ph↗
arXiv2022

Nonreciprocal frequency conversion with chiral $Λ$-type atoms

In this paper, we begin with a model of a $Λ$-type atom whose both transitions are chirally coupled to a waveguide and then extend the model to its giant-atom version. We investigate the single-photon scatterings of the giant-atom model in both the Markovian and non-Markovian regimes. It is shown that the chiral atom-waveguide couplings enable nonreciprocal, reflectionless, and efficient frequency conversion, while the giant-atom structure introduces intriguing interference effects to the scattering behaviors, such as ultra-narrow scattering windows. The chiral giant-atom model exhibits quite different scattering spectra in the two regimes and, in particular, demonstrates non-Markovicity induced nonreciprocity under specific conditions. These phenomena can be understood from the effective detuning and decay rate of the giant-atom model. Our results have potential applications in integrated photonics and quantum network engineering.

quant-ph↗
arXiv2019

Nonreciprocal quantum interference and coherent photon routing in a three-port optomechanical system

We study the quantum interference between different weak signals in a three-port optomechanical system, which is achieved by coupling three cavity modes to the same mechanical mode. If one cavity serves as a control port and is perturbed continually by a control signal, nonreciprocal quantum interference can be observed when another signal is injected upon different target ports. In particular, we exhibit frequency-independent perfect blockade induced by the completely destructive interference over the full frequency domain. Moreover, coherent photon routing can be realized by perturbing all ports simultaneously, with which the synthetic signal only outputs from the desired port. We also reveal that the routing scheme can be extended to more-port optomechanical systems. The results in this paper may have potential applications for controlling light transport and quantum information processing.

quant-ph↗