Experimental Observation of Dynamical Phase Transitions in a Dephased Photonic Quantum Walk
Authors:
Xiaojian Huang,
Lei Xiao,
Bingzi Huo,
Xiaowei Wang,
Stefano Longhi,
Peng Xue
Abstract:
Dynamical phase transitions in open quantum systems govern how non-equilibrium states relax toward a stationary state. We study these transitions experimentally using a discrete-time photonic quantum walk on a three-node graph. A tunable synthetic gauge flux and calibrated dephasing allow us to control time-reversal symmetry and the detailed balance properties of the effective Markovian dynamics.…
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Dynamical phase transitions in open quantum systems govern how non-equilibrium states relax toward a stationary state. We study these transitions experimentally using a discrete-time photonic quantum walk on a three-node graph. A tunable synthetic gauge flux and calibrated dephasing allow us to control time-reversal symmetry and the detailed balance properties of the effective Markovian dynamics. With detailed balance, we observe a first-order dynamical phase transition marked by a crossing of real Liouvillian eigenvalues. When detailed balance is broken, we observe a second-order dynamical phase transition at an exceptional point where eigenvalues and eigenvectors coalesce. By progressively reducing the dephasing strength, we track the crossover toward the quantum-coherent regime and determine that the transitions persist down to a finite threshold. Our results link Liouvillian spectral topology to relaxation criticality and demonstrate a controllable platform for engineered dissipative dynamics.
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Submitted 14 June, 2026;
originally announced June 2026.
Study on temperature coefficient of CdTe detector used for X-rays detection
Authors:
Si-Ming Guo,
Jin-Jie Wu,
Jian Zhang,
Xu-Fang Li,
Cong-Zhan Liu,
Shuai Zhang,
Cheng-Ze Li,
Bin-Bin Huo,
Zhen-Yu Liao
Abstract:
The temperature of the working environment is a key factor in determining the properties of semiconductor detectors, and it affects the absolute accuracy and stability of the standard detector. In order to determine the temperature coefficient of CdTe detector used for X-rays detection, a precise temperature control system was designed. In this experiment, detectors and radiographic source were se…
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The temperature of the working environment is a key factor in determining the properties of semiconductor detectors, and it affects the absolute accuracy and stability of the standard detector. In order to determine the temperature coefficient of CdTe detector used for X-rays detection, a precise temperature control system was designed. In this experiment, detectors and radiographic source were set inside the thermostat with temperature of 0-40 Celsius degree, so that the temperature can be regulated for the test of the temperature coefficient of CdTe detector. Studies had shown that, with the increase of the temperature, the energy resolution and detection efficiency of the CdTe detector would deteriorate, and under 10 Celsius degree the detectors have better performance with the 8 keV X-rays.
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Submitted 21 November, 2016;
originally announced November 2016.