Quantum Criticality in a 2DES

Ru-Qiong Deng, Cheng-Ge Liu, Yi-Xuan Yao +4 more

Dissipation and decoherence of quantum systems in thermal environments is important to various spectroscopies. It is generally believed that dissipation can broaden the line shape of spectroscopies, and thus stronger system-bath interaction can result in more significant homogeneous broadening of two-dimensional electronic spectroscopy (2DES). Here we show that the case can be the opposite in the regime of electromagnetically induced transparency (EIT). We predict that assisted by EIT, the homogeneous broadening of the 2DES at a higher temperature can be significantly reduced due to the detailed balance. This anomalous effect is due to the long-lasting off-diagonal peaks in 2DES.

Piers Coleman, A. J. Schofield

Jing-Yi-Ran Jin, Hao-Yue Zhang, Yi-Xuan Yao +2 more

Two-dimensional electronic spectroscopy (2DES) has high spectral resolution and is a useful tool for studying atomic dynamics. In this paper, we show a smallest unit of electromagnetically induced transparency (EIT) for 2DES, i.e., a three-level system. It is found that the original main peak is split into four small ones due to the introduction of EIT. It suggests that the homogeneous broadening of 2DES can be effectively reduced by EIT. Moreover, in sharp contrast to a constant height, the height of the peaks will manifest a damped oscillation with respect to the population time. It seems that the quantum-beat phenomenon appears. These findings may help us obtain more information about the dynamics of excited states.

Kaden R. A. Hazzard

K Biedermann, T. Matsuyama, U. Merkt

We investigate the high-frequency (rf) coupling of two Nb/InAs(2DES)/Nb Josephson junctions coupled by a superconducting microstrip. One junction acts as a transmitter and the other one as a receiver. We report on the influence of the transmitter junction on the critical current and on the Fiske resonances of the receiver junction for different geometrical designs.