N能级量子系统弛豫速率的限制

Universal Constraints on Relaxation Times for d-level GKLS master equations

In 1976, Gorini, Kossakowski, Sudarshan and Lindblad independently discovered a general form of master equations for an open quantum Markovian dynamics. In honor of all the authors, the equation is nowadays called the GKLS master equation. In this paper, we show universal constraints on the relaxation times valid for any d-level GKLS master equations, which is a generalization of the well-known constraints for 2-level systems. Specifically, we show that any relaxation rate, the inverse-relaxation time, is not greater than half of the sum of all relaxation rates. Since the relaxation times are …

On the universal constraints for relaxation rates for quantum dynamical semigroup

A conjecture for the universal constraints for relaxation rates of a quantum dynamical semigroup is proposed. It is shown that it holds for several interesting classes of semigroups, e.g. unital semigroups and semigroups derived in the weak coupling limit from the proper microscopic model. Moreover, proposed conjecture is supported by numerical analysis. This conjecture has several important implications: it allows to provide universal constraints for spectra of quantum channels and provides necessary condition to decide whether a given channel is consistent with Markovian evolution.

在D-Wave量子退火机上相互作用双量子比特系统能量弛豫速率的实验测量与理论分析

Experimental Measurement and Theoretical Analysis of Energy Relaxation Rates of an Interacting Two-Qubit System on a D-Wave Quantum Annealer

本研究在D-Wave量子退火机上测量并分析了单量子比特和相互作用双量子比特系统的能量弛豫速率，验证了局域噪声模型，并展示了利用单比特测量预测多比特系统弛豫速率的可行性。

Atomic multipole relaxation rates near surfaces

The spontaneous relaxation rates for an atom in free space and close to an absorbing surface are calculated to various orders of the electromagnetic multipole expansion. The spontaneous decay rates for dipole, quadrupole and octupole transitions are calculated in terms of their respective primitive electric multipole moments and the magnetic relaxation rate is calculated for the dipole and quadrupole transitions in terms of their respective primitive magnetic multipole moments. The theory of electromagnetic field quantization in magnetoelectric materials is used to derive general expressions f…

Purcell effect with microwave drive: Suppression of qubit relaxation rate

We analyze the Purcell relaxation rate of a superconducting qubit coupled to a resonator, which is coupled to a transmission line and pumped by an external microwave drive. Considering the typical regime of the qubit measurement, we focus on the case when the qubit frequency is significantly detuned from the resonator frequency. Surprisingly, the Purcell rate decreases when the strength of the microwave drive is increased. This suppression becomes significant in the nonlinear regime. In the presence of the microwave drive, the loss of photons to the transmission line also causes excitation of …

单量子比特和双量子比特哈密顿量和弛豫率的直接估计

Direct Estimation of Single- and Two-Qubit Hamiltonians and Relaxation Rates

我们提供了一种新的方法，通过利用一个单一的测量设备的量子哈密顿系统的特性。具体来说，我们演示了如何外部量子相关可以用于哈密顿识别任务。我们明确地介绍了直接估计单和双量子位哈密顿参数的实验程序，也为同时估计横向和纵向弛豫速率，使用一个单一的贝尔状态分析仪。我们的方法比以前的方法的一个优点是，它有一个内置的功能，这使得它适合部分表征的哈密顿参数。