Superfluorescence in a continuously pumped medium

Electrons, holes, and photons in semiconductors are interacting fermions and bosons. In this system, a variety of ordered coherent phases can be formed through the spontaneous phase symmetry breaking because of their interactions. The Bose-Einstein condensation (BEC) of excitons and polaritons is one of such coherent phases, which can potentially crossover into the Bardeen-CooperSchrieffer (BCS) type ordered phase at high densities under quasi-equilibrium conditions, known as the BCS-BEC crossover. In contrast, one can find the semiconductor laser, superfluorescence (SF), and superradiance as relevant phenomena under nonequilibrium conditions. In this paper, we present a comprehensive generating functional theory that yields nonequilibrium Green's functions in a rigorous way. The theory gives us a starting point to discuss these phases in a unified view with a diagrammatic technique. Comprehensible time-dependent equations are derived within the Hartree-Fock approximation, which generalize the Maxwell-Semiconductor-Bloch equations under the relaxation time approximation. With the help of this formalism, we clarify the relationship among these cooperative phenomena and we show theoretically that the Fermi-edge SF is directly connected to the e-h BCS phase. We also discuss the emission spectra as well as the gain-absorption spectra.

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“…For this purpose, the BSEs [ Figure 18; Eqs. (120) and (121)] is now available together with Eq. (122).…”

Section: Evaluation Of the Two-particle Gfsmentioning

confidence: 99%

Generating functional approach for spontaneous coherence in semiconductor electron-hole-photon systems

Yamaguchi¹,

Nii²,

Kamide³

et al. 2015

Phys. Rev. B

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“…An essential element in the stochastic simulations is a proper characterization of the Langevin noises. These represent the quantum fluctuations responsible for the initiation of the spontaneous emission from the inverted [32,[52][53][54], or pumped atomic system [55,56] as in our case.…”

Section: Introductionmentioning

confidence: 99%

Positive-Pphase-space-method simulation of superradiant emission from a cascade atomic ensemble

Jen

2012

Phys. Rev. A

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The superradiant emission properties from an atomic ensemble with cascade level configuration is numerically simulated. The correlated spontaneous emissions (signal then idler fields) are purely stochastic processes which are initiated by quantum fluctuations. We utilize the positive-P phase space method to investigate the dynamics of the atoms and counter-propagating emissions. The light field intensities are calculated, and the signal-idler correlation function is studied for different optical depths of the atomic ensemble. Shorter correlation time scale for a denser atomic ensemble implies a broader spectral window needed to store or retrieve the idler pulse.

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“…In this case, the antidamping rate will be enhanced by a factor of N, where N is the number of atoms [25][26][27]. The M coefficients in the above input-output relation can be written as…”

Section: B Extension To Many-atom Casementioning

confidence: 99%

Quantum noise of a white-light cavity using a double-pumped gain medium

Ma¹,

Miao

Zhao³

et al. 2015

Phys. Rev. A

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Laser interferometric gravitational-wave detectors implement Fabry-Pérot cavities to increase their peak sensitivity. However, this is at the cost of reducing their detection bandwidth, which originates from the propagation phase delay of the light. The "white-light-cavity" idea, first proposed by Wicht et al. [Opt. Commun. 34, 431 (1997)], is to circumvent this limitation by introducing anomalous dispersion, using a double-pumped gain medium, to compensate for such a phase delay. In this article, starting from the Hamiltonian of the atom-light interaction, we apply an input-output formalism to evaluate the quantum noise of the system. We find that apart from the additional noise associated with the parametric amplification process noted by others, the stability condition for the entire system poses an additional constraint. By surveying the parameter regimes where the gain medium remains stable (not lasing) and stationary, we find that there is no net enhancement of the shot-noise-limited sensitivity. Therefore, other gain media or different parameter regimes should be explored for realizing the white-light cavity.

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Superfluorescence in a continuously pumped medium

Cited by 18 publications

References 14 publications

Generating functional approach for spontaneous coherence in semiconductor electron-hole-photon systems

Generating functional approach for spontaneous coherence in semiconductor electron-hole-photon systems

Positive-Pphase-space-method simulation of superradiant emission from a cascade atomic ensemble

Quantum noise of a white-light cavity using a double-pumped gain medium

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