Fundamental trade-off between the speed of light and the Fano factor of photon current in three-level lambda systems

Quantum Memory for Photons in Case of Many Close Lying Exciton Resonances in Solids

The possibility of storage of quantum information with photons is studied in the case of resonant transitions via many close lying exciton levels in a solid with impurity Lambda-atoms. The upper levels of the impurity atom form resonant Fano states, similar to the autoionization atomic states, due to the configuration interaction with the continuum of the exciton band. In this case slowing of light pulses is shown to be realistic, in the presence of the control field, down to the group velocity much lower than that in vacuum. The possibility of storage and reconstruction of a quantum pulse is …

A unified approach to $Λ$-, $Ξ$- and $V$-type systems with one continuum

We present a systematic approach to classify the three-level-like models with two bound states coupled to a continuum. It is shown that, when one of the discrete levels of usual three-level Lambda- ($Λ$), cascade ($Ξ$) or Vee ($V$)-type systems is replaced by a continuum of states, the resulting each model can be classified into three distinct categories with nine possible configurations. We show that all these models are exactly solvable. We obtain and compare the asymmetric Fano line shapes of the spectra for all the models. Our results are important for exploring new coherent effects in a v…

弗洛凯量子热晶体管中的涨落与最优控制

Fluctuations and optimal control in a Floquet Quantum Thermal Transistor

本研究采用全计数统计方法，对三端弗洛凯量子热晶体管进行建模，通过分段随机基优化协议实现最优控制，发现精度与基极电流间存在权衡，成果或助力量子热调制装置研发。

脉泽热机中动力学不确定关系的违反：自发辐射的作用

Violation of kinetic uncertainty relation in maser heat engines: Role of spontaneous emission

本研究通过比较脉泽热机的两种构型，发现自发辐射导致的退相干速率差异是KUR违反与否的决定性因素，为控制退相干以提升量子热机性能提供了指导。

Role of the phase-matching condition in non-degenerate four-wave mixing in hot vapors for the generation of squeezed states of light

Non-degenerate forward four-wave mixing in hot atomic vapors has been shown to produce strong quantum correlations between twin beams of light [McCormick et al, Opt. Lett. 32, 178 (2007)], in a configuration which minimizes losses by absorption. In this paper, we look at the role of the phase-matching condition in the trade-off that occurs between the efficiency of the nonlinear process and the absorption of the twin beams. To this effect, we develop a semi-classical model by deriving the atomic susceptibilities in the relevant double-lambda configuration and by solving the classical propagati…

Pushing Purcell-enhancement beyond its limits

Purcell-enhanced emission from a coupled emitter-cavity system is a fundamental manifestation of cavity quantum electrodynamics. Starting from a theoretical description we derive a scheme for photon emission from an emitter coupled to a birefringent cavity that exceeds hitherto anticipated limitations. Based on a recent study and experimental investigation of the intra-cavity coupling of orthogonal polarisation modes in birefringent cavities, we now decouple the emitter and the photon prior to emission from the cavity mode. Effectively, this is "hiding" the emitter from the photon in the cavit…