Sensing single atoms in a cavity using a broadband squeezed light

Abstract

We investigate a single atom cavity-QED system directly driven by a broadband squeezed light.We demonstrate how the squeezed radiation can be used to sense the presence of a single atom in a cavity. This happens by transferring one of the photons from the field in a state with even number of photons to the atom and thereby populating odd number Fock states. Specifically, the presence of the atom is sensed by remarkable changing in the presence of one photon and the loss of squeezing of the cavity field. A complete study of quantum fluctuations and the excitation of multiphoton transitions is given.

Non-equilibrium scalar field dynamics starting from Fock states: Absence of thermalization in one dimensional phonons coupled to fermions

“…Several problems in non-equilibrium dynamics relevant to different branches of physics require the description of dynamics of scalar fields starting from athermal initial conditions. Such initial conditions can result from sophisticated pulse-shaping techniques creating squeezed lights in optical cavities 39,44,45 . They can also be created when large amount of energy is dumped into a system with broken symmetry as is done in the case of pump-probe experiments [29][30][31][32][70][71][72] .…”

“…In many of these cases, the system evolves starting from an athermal state. A typical example is a cavity where the photons are initiated to a squeezed state 39,[42][43][44][45] . Thus it is very important to obtain a description of dynamics of scalar fields starting from athermal initial conditions.…”

Detecting a single atom in a cavity using the $χ^{(2)}$ nonlinear medium

“…This problem has attracted considerable attentions. Up to now, there have been proposed several single-atom detection schemes [37][38][39][40][41][42][43][44][45][46][47]. For instance, detecting atoms in dipole traps using fluorescence detections [37,38], detecting a single atom using photonic bandgap cavities [39], sensing single atoms in a cavity using broadband squeezed light [40], qubit measurement by interferometry with parametric amplifiers [41].…”

“…Up to now, there have been proposed several single-atom detection schemes [37][38][39][40][41][42][43][44][45][46][47]. For instance, detecting atoms in dipole traps using fluorescence detections [37,38], detecting a single atom using photonic bandgap cavities [39], sensing single atoms in a cavity using broadband squeezed light [40], qubit measurement by interferometry with parametric amplifiers [41]. In addition, the enhanced coupling between atoms and photons inside a highfinesse optical cavity provides a novel basis for optical measurements that continuously monitor atomic degrees of freedom.…”

“…Observing a single atom in a blue-detuned intracavity dipole trap, the blue "funnels" demonstrated in this scheme could efficiently guide an atom to regions of strong atom-cavity coupling, thereby enhancing the detection efficiency in the experiments of single-atom detection [50]. However, these schemes have some drawbacks, for example, at present, the direct coupling of broadband squeezed vacuum field and cavity is hard to realize experimentally [40], and the squeezed strength is difficult to control, which may hinder the implementations of the experiment.…”