研究方向
1. 凝聚态强关联系统
研究二能级原子与腔耦合的量子多体系统，比如 Dicke 模型、spin-boson 模型，从量子信息角度分析量子相变等物理现象。
代表作：
- (1) Xiang-You Chen, Yu-Yu Zhang, Finite-size scaling analysis in the two-photon Dicke model, Phys. Rev. A 97, 053821 (2018).
- (2) Chen Wang, Yu-Yu Zhang, Qing-Hu Chen, Quantum correlations in collective spin systems, Phys. Rev. A 85, 052112 (2012). (cited: 25)
- (3) Yu-Yu Zhang, et al., Quantum phase transition in the Sub-Ohmic Spin-Boson model: Extended coherent-state Approach, Phys. Rev. B 81, 121105 (Rapid Communication) (2010) (Editor's Suggestion). (cited: 48)
- (4) Qinghu Chen, Tao Liu, Yu-Yu Zhang, Ke-Lin Wang, Quantum phase transition in coupled two-level atoms in a single-mode cavity, Phys. Rev. A 82, 053841 (2010). (cited: 13)
- (5) Tao Liu, Yu-Yu Zhang, et al., Large-N scaling behavior of the ground-state energy, fidelity, and the order parameter in the Dicke model, Phys. Rev. A 80, 023810 (2009). (cited: 39)
- (6) Qing-Hu Chen, Yu-Yu Zhang, Tao Liu, Ke-Lin Wang, Numerically exact solution to the finite-size Dicke model, Phys. Rev. A 78, 051801 (Rapid Communication) (2008). (cited: 92)
2. 量子光学与腔电动力学（QED）
研究量子比特-超导腔耦合系统，以及光与物质作用的量子光学理论模型解析方法，比如相干态方法、压缩相干态方法等。
代表作：
- (1) Yu-Yu Zhang, Xiang-You Chen, Analytical solutions by squeezing to the anisotropic Rabi model in the nonperturbative deep-strong coupling regime, Phys. Rev. A 96, 063821 (2017).
- (2) Yu-Yu Zhang, Generalized squeezing rotating-wave approximation to the isotropic and anisotropic Rabi model in the ultrastrong-coupling regime, Phys. Rev. A 94, 063824 (2016). (cited: 5)
- (3) Yu-Yu Zhang, et al., Analytical solutions and genuine multipartite entanglement of the three-qubit Dicke model, Phys. Rev. A 94, 012317 (2016). (cited: 2)
- (4) Yu-Yu Zhang, et al., Generalized rotating-wave approximation for the two-qubit quantum Rabi model, Phys. Rev. A 91, 013814 (2015). (cited: 9)
- (5) Yu-Yu Zhang, et al., Generalized rotating-wave approximation to biased qubit-oscillator systems, Phys. Rev. A 87, 033827 (2013). (cited: 10)
- (6) Qing-Hu Chen, Tao Liu, Yu-Yu Zhang, Ke-Lin Wang, Exact solutions to the Jaynes-Cummings model without the rotating-wave approximation, EPL 96, 14003 (2011). (cited: 31)