Three-Photon Correlations in a Strongly Driven Atom-Cavity System

Abstract

The quantum dynamics of a strongly driven, strongly coupled single-atom-cavity system is studied by evaluating time-dependent second-and third-order correlations of the emitted photons. The coherent energy exchange, first, between the atom and the cavity mode, and second, between the atom-cavity system and the driving laser, is observed. Three-photon detections show an asymmetry in time, a consequence of the breakdown of detailed balance. The results are in good agreement with theory and are a first step towards the control of a quantum trajectory at larger driving strength.Open quantum systems far from thermal equilibrium hold great promise for the investigation of fundamental physics and the implementation of practical devices [1, 2]. The versatility of such systems comes from two features: the coherent evolution induced by the driving and the dissipation enabling a transfer of information to an observer. These two characteristics affect each other, and the deterministic evolution is interrupted by unpredictable quantum jumps [3, 4]. Monitoring such a quantum trajectory is a challenge, in particular when many quantum states must be discriminated from each other. A model system in this context is provided by optical cavity quantum electrodynamics (QED) in the regime of strong lightmatter coupling, where atomic and photonic observables have been tracked in real time [5][6][7][8] and controlled by means of feedback [9][10][11]. However, these experiments were performed at low excitation. Stronger driving and, hence, faster probing would allow one to track the system more closely and explore high-intensity effects like the coherent coupling of the system with the drive laser or the dynamical polarization of the dressed states [12,13]. Moreover, higher excited states containing several photons should be discernible by characteristic patterns of multiple-photon emissions [14], which can be asymmetric in time due to the predicted breakdown of detailed balance [15]. In this Letter we explore such patterns for a strongly driven atom-cavity system, when the excitation rate exceeds the dissipative rates.We consider a system where the atom-cavity coupling strength g 0 exceeds the atomic polarization decay rate γ and the cavity field decay rate κ. The internal dynamics, described by the Jaynes-Cummings Hamiltonian, is complemented by driving with a probe laser of strength η [31] and dissipation due to spontaneous emission and cavity decay. By monitoring the photon stream from the cavity, one can evaluate different observables such as the average photon number, a † a , or the average number of photon pairs, a †2 a 2 . The first is interesting, e.g., in the context of normal-mode spectroscopy [16,17], while insight into quantum effects can be obtained by regarding photon pairs [14,18]. Due to the interplay of the different dynamical processes, both observables are expected

Nonclassical higher-order photon correlations with a quantum dot strongly coupled to a photonic-crystal nanocavity

“…A more detailed analysis of the dark state dynamics can be obtained using a rate equation approach [24], but that is beyond the scope of this work. Unfortunately, because of the much faster time-scales of our system compared to conventional atom-cavity experiments [13], we cannot resolve the decay rate of photon bunching caused by photon-induced tunneling, as this happens within the time scale of the individual pulses. After normalization, the second-order autocorrelation isḡ (2) (0) =G (2) 0 /Ḡ (2) ∞ = 1.141 ± 0.003 (we use the notationḡ (2) to indicate we have both timebinned and normalized the raw coincidence counts, so this represents our experimental measurement of the theoretical value g (2) ).…”

“…Very recently g (3) measurements of the fluorescence from a single quantum dot weakly coupled to a microcavity were reported as well [12]. However, in the low-intensity, strongly-coupled regime of cavity quantum electrodynamics, such correlations have only been measured in an atomic system [13]. Therefore, this work constitutes a significant step towards implementing a solidstate non-classical light source of photon number states.…”

Quantum nonlinear optics — photon by photon

“…In particular, the strong atom-photon coupling yields an extra interaction energy cost to populate the system with n photons, as compared with an empty cavity in which n photons have an energy corresponding to n times that of a single photon. This feature can be used to generate non-classical light by tuning the excitation laser to the corresponding transition frequency of the nonlinear Jaynes-Cummings ladder, as demonstrated in experiments with a single atom trapped inside a high-finesse optical resonator 27,34,35 (Fig. 1).…”

Atom-mediated effective interactions between modes of a bimodal cavity

“…In this section, we discuss some aspects about current experimental feasibility of our proposal considering different experimental setups of CQED [1,6]. In the experimental setup of Haroche et al [1,3,11,44], Rydberg atoms (rubidium) are coupled to a microwave high quality superconductivity cavity.…”

“…The same setup was also used to reconstruct the Wigner function of Fock states with more than one photon [3]. Recently, CQED setups has been used in order to study three-photon correlations [6], the apparition of electromagnetically induced transparency using Rubidium [7] and Cesium [8] single atoms and quantum jumps [9,10].…”