Bao-Yun Dong, Ying Liang, Stefano Chesi, Xue-Feng Zhang
We study the properties of a generalized Dicke-Ising model realized with an array of Rydberg atoms, driven by microwave electric fields and coupled to an optical cavity. As this platform allows for a precisely tunable anisotropy parameter, the model exhibits a rich landscape of phase transitions and critical phenomena, induced by the interplay of rotating-wave, counter-rotating-wave, and Ising interactions. We develop an improved quantum Monte Carlo algorithm based on the stochastic series expansion that explicitly tracks the Fock state of the quantum cavity. In the superradiant (SR) phase, this allows us to determine, through data collapse, the scaling laws of the photon number. We also demonstrate the vanishing of parity symmetry in finite-size simulations and show that the Rydberg blockade leads to a significant suppression of cavity occupation. Notably, stronger quantum fluctuations induced by the counter-rotating wave terms slightly favor the superradiant solid (SRS) phase over the Solid-1/2 state. Finally, we confirm that the SR phase transition and the transition from the Solid-1/2 to the SRS are second-order. In contrast, the transitions from the Solid-1/2 or SRS to the SR phase are both first-order for any value of the normalized anisotropy parameter.
Bao-Yun Dong, Yanhua Zhou, Wei Wang, Tao Wang
Mar 18, 2025·quant-ph·PDF The anisotropic Dicke model reveals the important role that counter-rotating wave terms play in the coupling between light and two level atoms. It is intriguing to generate the model to the strongly correlated many body case, where the competition between atomic interaction and light-atom coupling will induce exotic phenomenon. In this paper, we provide a periodically driving method for engineering an anisotropic Dicke model with strong dipole-dipole interaction between atoms based on Rydberg atom arrays in cavity. By modulating the pumping laser, the ratio of counter-rotating wave terms to rotating ones could be tuned from zero to infinity. As an illustrative example, the superiority of this tunability in the adiabatic state preparation is revealed. Our engineered model provides an extensive foundation for subsequet research of quantum simulation, many-body physics and even information processing.
Ying Liang, Bao-Yun Dong, Zi-Jian Xiong, Xue-Feng Zhang
Rydberg atom triangular arrays in an optical cavity serve as an ideal platform for understanding the interplay between geometric frustration and quantized photons. Using a large-scale quantum Monte Carlo method, we obtain a rich ground state phase diagram. Around half-filling, the infinite long-range light-matter interaction lifts the ground state degeneracy, resulting in a novel order-coexisted superradiant clock phase that completely destroys the fragile order-by-disorder phase observed in classical light fields. According to the Ginzburg-Landau theory, this replacement may result from the competition between threefold and sixfold clock terms. Similar to the spin supersolid, the clear first-order phase transition at the $Z_2$ symmetry line is attributed to the nonzero photon density, which couples to the threefold clock term. Finally, we discuss the low-energy physics in the dimer language and propose that cavity-mediated nonlocal ring exchange interactions may play a critical role in the rich physics induced by the attachment of cavity-QED. Our work opens a new arena of research on the emergent phenomena of quantum phase transitions in many-body quantum optics.