Theory of the Microscopic Maser Phase Transitions

Positivity of entropy production for the three-level maser

Entropy production is a key concept of thermodynamics and allows one to analyze the operation of engines. For the Scovil-Schulz-DuBois heat engine, the archetypal three-level thermal maser coupled to thermal baths, it was argued that the common definition of heat flow may provide negative entropy production for certain parameters [E. Boukobza and D. J. Tannor, Phys. Rev. Lett. 98, 240601 (2007)]. Here, we show that this can be cured, if corrections for detuning are properly applied to the energies used for the bath transitions. This method can be used more generally for the thermodynamical ana…

Phonon-Assisted Gain in a Semiconductor Double Quantum Dot Maser

We develop a microscopic model for the recently demonstrated double quantum dot (DQD) maser. In characterizing the gain of this device we find that, in addition to the direct stimulated emission of photons, there is a large contribution from the simultaneous emission of a photon and a phonon, i.e., the phonon sideband. We show that this phonon-assisted gain typically dominates the overall gain which leads to masing. Recent experimental data are well fit with our model.

室温无反转金刚石氮空位电子自旋微波激射器

Room-temperature inversionless diamond nitrogen-vacancy electronic spin maser

该研究提出利用金刚石中带负电的氮空位电子自旋系综创建室温微波激射器的方法。通过施加垂直直流磁场产生叠加态驱动跃迁，建模并经数值估计可实现无反转微波激射，其输出强度可用于磁场传感，为室温NV微波激射器应用开辟新方向。

Threshold Dynamics of a Semiconductor Single Atom Maser

We demonstrate a single-atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high quality factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masin…

原子微波激射器中的大偏差、中心极限与动力学相变

Large Deviations, Central Limit and dynamical phase transitions in the atom maser

本文利用形变生成元、Gärtner–Ellis 定理与 Krein–Rutman 理论证明原子微波激射器探测计数满足大偏差原理并导出中心极限定理，指出有限泵浦下为相位交叉，真正相变仅出现在无限泵浦极限。