Photophysics of a single quantum emitter based on vanadium phthalocyanine molecules.

Single quantum emitters play a fundamental role in the development of quantum technologies such as quantum repeaters, and quantum information processing. Isolating individual molecules with stable optical emission is an essential step for these applications, especially for those molecules that present large coherence times at room temperature. Among them, vanadium-oxide phthalocyanine (VOPc) molecules stand out as promising candidates due to the large coherence times of their ground state electronic spin, which are on the order of microseconds when measured in the ensemble.

Temperature-Dependent Photophysics of Single NV Centers in Diamond.

We present a comprehensive study of the temperature- and magnetic-field-dependent photoluminescence (PL) of individual NV centers in diamond, spanning the temperature-range from cryogenic to ambient conditions. We directly observe the emergence of the NV's room-temperature effective excited-state structure and provide a clear explanation for a previously poorly understood broad quenching of NV PL at intermediate temperatures around 50 K, as well as the subsequent revival of NV PL. We develop a model based on two-phonon orbital averaging that quantitatively explains all of our findings, including the strong impact that strain has on the temperature dependence of the NV's PL.

Temperature-Dependent Spin-Lattice Relaxation of the Nitrogen-Vacancy Spin Triplet in Diamond.

Spin-lattice relaxation within the nitrogen-vacancy (NV) center's electronic ground-state spin triplet limits its coherence times, and thereby impacts its performance in quantum applications. We report measurements of the relaxation rates on the NV center's |m_{s}=0⟩↔|m_{s}=±1⟩ and |m_{s}=-1⟩↔|m_{s}=+1⟩ transitions as a function of temperature from 9 to 474 K in high-purity samples. We show that the temperature dependencies of the rates are reproduced by an ab initio theory of Raman scattering due to second-order spin-phonon interactions, and we discuss the applicability of the theory to other spin systems.

Ultrasonography performed by an infectiologist in hip and knee prosthetic joint and native joint infections.

Introduction: Clinical ultrasonography (US) by infectiologists has only recently been developing, and as now there is little literature on the subject. Our study focuses on the conditions and diagnostic performance of clinical ultrasound imaging by infectiologists in cases of hip and knee prosthetic and native joint infection.

Methods: A retrospective study carried out between June 1st 2019 and March 31st 2021 in the University Hospital of Bordeaux, South-Western France.

Collective enhancement in dissipative quantum batteries.

We study a quantum battery made out of N nonmutually interacting qubits coupled to a dissipative single electromagnetic field mode in a resonator. We quantify the charging energy, ergotropy, transfer rate, and power of the system, showing that collective enhancements are still present despite losses, and can even increase with dissipation. Moreover, we observe that a performance deterioration due to dissipation can be reduced by scaling up the battery size.