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Influence of impurity on the rate of single photon superradiance and photon transport in disordered N qubit chain
摘要： We investigate the rate of superradiant emission for a number of artificial atoms (qubits) embedded in a one-dimensional open waveguide. More specifically, we study the 1D (N+1)- qubit chain where N qubits are identical with respect to their excitation frequency Ω but have different rates of spontaneous emission Γn, and a single impurity qubit which is different from N qubits by its excitation frequency ΩP and the rate of spontaneous emission ΓP . We performed exact diagonalization of Hamiltonian and showed that the system has two hybridized collective states one of which accumulates the widths of all qubits. The energy spectrum of these states and corresponding probabilities are investigated as a function of the frequency detuning between the impurity and other qubits in a chain. It is shown that the inclusion of the impurity qubit alters the resonance widths of the system if the total width overlaps the frequency detuning between qubits and the impurity. In this case the resonance widths experience a significant repulsion. The photon transmission through disordered N- qubit chain with the impurity qubit is also considered. It is shown that a single photon transport through this system is described by a simple expression which predicts for specific photon frequency the existence of a complete transmission peak and transparency window between frequencies Ω and ΩP .
关键词： superradiance,impurity,photon transport,qubit chain,non-Hermitian Hamiltonian
更新于2025-09-23 15:23:52
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Superradiance and Collective Gain in the Atom-Assisted Multimode Optomechanical System
摘要： We investigate that the muti-mode optomechanical system coupled with the two-level atoms. If the driving pump field is resonance with the anti-Stokes sideband, the system is at the superradiative state. For the driving filed in the Stokes sideband, the collective gain can be observed. We study a scheme that how the atomic medium affect these superradiance and collective gain. Our results show that the presence of the atom can enhance the superradiant behavior. In the mode splitting regime, the mode splits into thirds with the presence of the atoms with the anti-Stokes sideband. In addition, we also show that the use of atoms in this system could provide us a way to switch the system form superradiative state to collective gain.
关键词： Anti-stoke sideband,Stokes sideband,Atoms,Collective gain,Superradiance,Optomechanical system
更新于2025-09-23 15:23:52
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Plasma effects on lasing of a uniform ultralight axion condensate
摘要： Lasing of an ultralight axion condensate into photons can be sensitive to the presence of a background plasma owing to its coupling to electromagnetism. Such a scenario is particularly relevant for a superradiant axion condensate around stellar mass black holes since the axion mass can be within a few orders of magnitude of the plasma frequency of the surrounding medium. In this paper, I discuss the properties of the plasma around a black hole and analyze its effects on the lasing of a uniform axion condensate of mass of the order of the plasma frequency.
关键词： superradiance,lasing,black holes,axion condensate,plasma effects
更新于2025-09-23 15:21:21
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Impact of Transient Population Grating on the Superradiant Phase Transition in Semiconductor Laser Structures
摘要： We study theoretically and experimentally superradiant dynamics in multiple-section GaAs/AlGaAs laser structures. We develop a model based on the one-dimensional Maxwell curl equations without making use of the slowly-varying envelope approximation and demonstrate that strong transient periodic modulation of both e – h density and refractive index drastically affect the dynamics of emission generation in semiconductor media. We show that the coherent λ/2 transient population and the relative permittivity gratings facilitate e – h self-ordering and the onset of the superradiant phase transition in the e – h system.
关键词： self-organization,superradiance,phase transition,population grating
更新于2025-09-23 15:21:01
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Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities
摘要： We discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH [1, 2], we show that, in absence of direct intercavity scattering and for parameters chosen such that the atoms couple symmetrically to both cavities, the system possesses an approximate U(1) symmetry which holds asymptotically for vanishing cavity field intensity. It corresponds to the invariance with respect to redistributing the total intensity = + I 2 between the two cavities. The spontaneous breaking of this symmetry gives rise to a broken continuous translation-invariance for the atoms, creating a supersolid-like order in the presence of a Bose–Einstein condensate. In particular, we show that atom-mediated scattering between the two cavities, which favors the state with equal light intensities =I 2, gives 1 rise to a finite value ~ I of the effective Goldstone mass. For strong atom driving, this low energy mode is clearly separated from an effective Higgs excitation associated with changes of the total intensity I. In addition, we compute the spectral distribution of the cavity light field and show that both the Higgs and Goldstone mode acquire a finite lifetime due to Landau damping at non-zero temperature.
关键词： superradiance,ultracold atoms,self-ordering,symmetry breaking,supersolidity,cavity QED,Goldstone mode
更新于2025-09-23 15:21:01
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Single-photon superradiance in waveguide-quantum-electrodynamical systems with whispering-gallery-mode resonators
摘要： As a manifestation of cooperative interactions between a single photon and a cluster of atoms, single-photon superradiance has attracted considerable attention recently but has been studied insofar as that only quantum emitters are involved in the superradiance process. Here we expand the scope of investigation to study single-photon superradiance in a waveguide-quantum-electrodynamical system containing whispering-gallery-mode (WGM) resonators which are essential for many nanophotonic devices. It is shown analytically and numerically that single-photon superradiance can also occur when WGM resonators are present. The criteria for the emergence of the superradiant emission peak and the enhanced atom-light coupling strength are derived. Finally, the general case of a cascade of WGM resonators is investigated by a renormalization approach. Single-photon frequency comb generation is demonstrated via a frequency-modulated superradiant effective atom in chiral waveguide-quantum-electrodynamical systems with WGM resonators.
关键词： single-photon superradiance,whispering-gallery-mode resonators,atom-light coupling,waveguide-quantum-electrodynamical systems,frequency comb generation
更新于2025-09-23 15:19:57
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Phononic-waveguide-assisted steady-state entanglement of silicon-vacancy centers
摘要： Multiparticle entanglement is of great significance for quantum metrology and quantum information processing. We present here an efficient scheme for generating stable multiparticle entanglement in a solid-state setup, where an array of silicon-vacancy centers are embedded in a quasi-one-dimensional acoustic diamond waveguide. In this scheme, the continuum of phonon modes induces a controllable dissipative coupling among the SiV centers. We show that, by an appropriate choice of the distance between the SiV centers, the dipole-dipole interactions can be switched off due to destructive interference, thus realizing a Dicke superradiance model. This gives rise to an entangled steady state of SiV centers with high fidelities. The protocol provides a feasible setup for the generation of multiparticle entanglement in a solid-state system.
关键词： Multiparticle entanglement,quantum information processing,acoustic diamond waveguide,quantum metrology,silicon-vacancy centers,Dicke superradiance model
更新于2025-09-19 17:13:59
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Weak superradiance in arrays of plasmonic nanoantennas
摘要： A collection of N emitters can exhibit an N-fold broadening of the radiative linewidth resulting from the development of a macroscopic dipole moment. Such a broadening of the radiative linewidth has previously been observed in systems of several nanoparticles and has often been described in terms of superradiant behavior. However, the understanding of the physics behind the observed dependence of radiative linewidth on the number of irradiated nanoparticles is far from complete. In this paper, we present theoretical and experimental results that elucidate this broadening mechanism in plasmonic systems and draw a connection with the phenomenon of Dicke superradiance. We demonstrate that, in the limit where radiative broadening dominates, the extinction linewidth of a planar array of plasmonic nanoantennas scales linearly with the number of nanoantennas contained within a circle of radius equal to the resonant optical wavelength. We explain this classical phenomenon as a weak superradiance effect, which corresponds to the case in the Dicke model where only the ground state and the first collective excited state contribute to the enhanced radiation.
关键词： superradiance,radiative linewidth,Dicke model,plasmonic nanoantennas,collective behavior
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Superradiance as a Way to the Steady-State Multimode and Ultrashort Pulsed Lasing in CW Quantum-Dot Heterolasers
摘要： On the basis of the Maxwell-Bloch equations, we demonstrate theoretically and numerically that the pulsed superradiant lasing is possible in the quantum-dot heterostructures under continuous-wave (CW) optical pumping if the quantum-dot coherence lifetime exceeds the photon lifetime in a laser cavity [1, 2]. We analyze/compare in detail and select the most promising multilayered well-dot and sub-monolayer quantum-dot heterostructures which could be used as the active media, and design for them the proper low-Q combined Fabry-Perot cavities with distributed feedback which will select the superradiant modes. We investigate various operational regimes of the superradiant lasing and the intriguing quantum-coherent features of both cooperative and individual dynamics of quantum dots under the action of a self-consistent intracavity field preserving the long-term and wide-spectral coherence. Among the remarkably diverse operational regimes of the laser, we find the quasi-stationary, self-modulated, regular or irregular pulsed, self-locked, and stochastic regimes. In particular, we show that one or several superadiant modes may emit the quasiperiodic sequences of ultrashort subpicosecond pulses with comparable periods of the order of picoseconds and at the same time give rise to many steady-state modes with quasi-equidistant spectrum (see a fig. 1). The letter used to be self-locked due to the superradiant coherent dynamics of quantum dots, so that an additional sequence of ultrashort subpicosecond pulses with a round-trip period are emitted in the absence of any active or passive mode-locking elements. We indicate the ways how (i) to overcome an additional relaxation of the quantum-dot coherence in the presence of incoherent pumping and suppression of the superradiant gain within an inhomogeneously broadened spectral line of quantum dots continuously, i.e., during the entire time of laser operation, and (ii) to ensure a fully cycling pump-emission scheme of the quantum dots’ dynamics including a fast depletion of the lower-energy states under a CW pumping of the upper-energy states and to minimize extra heating which accompanies this cycling process and increases the relaxation of coherence. The suggested pulsed multimode superradiant heterolaser will offer a number of applications in the information optics, data processing, fiber network systems, wideband dynamic spectroscopy and diagnostics of various materials since it will be the first compact source of coherent radiation with a wide variety of controllable quantum-correlation and spectral-temporal properties. Also, such a heterolaser is a unique object for the studies of complex coherent processes in the semiconductor heterostructures.
关键词： Continuous-Wave Optical Pumping,Ultrashort Pulsed Lasing,Quantum-Dot Heterolasers,Maxwell-Bloch Equations,Superradiance
更新于2025-09-12 10:27:22
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Relativistic microwave oscillators with high power flux in a free space and interaction zone
摘要： In the recent two decades, high-power microwave (HPM) generators producing short Ka-band and X-band pulses were intensively investigated (see Refs. [1–6] and citation therein). For generation of HPM pulses with duration of units of nanosecond and less influence of microwave breakdowns of electrodynamics systems, expansion of cathode and collector plasmas, and electron beam structure distortions becomes insignificant. Though the pulse duration is short, the radiating energy rises if coherent summation of radiation from several generators is provided. When the power in each channel is high, the wave beam could be formed where power flux density is limited only by breakdown strength of the media. Using approaches of the phased arrays, the directional pattern (DP) of summarized radiation could be steered. This is achievable from pulse to pulse, as well as during a single nanosecond pulse if summarized wave beams have a shifted frequencies. The related experiments with Ka-band microwave pulses are presented below.
关键词： directional pattern,Ka-band,phased arrays,superradiance,microwave breakdowns,backward-wave oscillators,X-band,coherent summation,high-power microwave
更新于2025-09-10 09:29:36