arXiv subjects

Lavakumar Addepalli

Publications and source records attributed to Lavakumar Addepalli.

4 recordsLinked to original sources

arXiv2025

Multi-Photon Lasing Phenomena in Quantum Dot-Cavity QED

Multi-photon lasing has been realized in systems with strong nonlinear interactions between emitters and cavity modes, where single-photon processes are suppressed. Coherence between the internal states of a quantum emitter, or among multiple emitters, plays a key role. Such continuous nonclassical sources of light can find applications in quantum computation, quantum sensing, quantum metrology, and quantum communication. This thesis explores the multi-photon lasing phenomena in various quantum dot-photonic crystal cavity quantum electrodynamic (QED) setups. Exciton-phonon interactions are inevitable in such systems and are incorporated using the polaron-transformed master equation. The Born-Markov approximation is employed to obtain the reduced density matrix rate equation. Using quantum laser theory, we derived the Scully-Lamb laser rate equations and evaluated the single- and multi-photon excess emission rates defined as the difference between emission and absorption rates into the cavity mode without mean-field approximations. We investigated cooperative two-photon lasing, correlated emission lasing, hyperradiant lasing, non-degenerate two-mode two-photon lasing, and continuous variable entanglement in open quantum systems with single or multiple semiconductor quantum dots (two-level, three-level, and four-level) driven coherently/incoherently and coupled to single/ bimodal cavities.

quant-ph↗

arXiv2025

Two-mode hyperradiant lasing in a system of two quantum dots embedded in a bimodal photonic crystal cavity

We propose a scheme for two-mode hyperradiant lasing in a system comprising two incoherently pumped quantum dots (QDs) coupled to a bimodal photonic crystal cavity. To account for the exciton-phonon interactions, we employ a time-convolutionless polaron-transformed master equation. Both resonant and off-resonant couplings of the QDs to the cavity modes are considered, and we analyze the resulting radiance witness as well as the intra- and inter-mode photon correlations. Furthermore, we demonstrate that phonon-induced cooperative two-mode two-photon processes significantly enhance the radiance witness. This enhancement is quantified by evaluating the emission and absorption rates associated with both single-mode and two-mode two-photon transitions. Finally, we compare the radiance witness and emission spectral linewidths for QDs coupled to single-mode and bimodal cavities, revealing that an increase in radiance witness is accompanied by a narrowing of the emission linewidth.

quant-ph↗

arXiv2024

Correlated emission lasing in a single quantum dot embedded inside a bimodal photonic crystal cavity

We investigate the phenomenon of correlated emission lasing in a coherently driven single quantum dot coupled to a bimodal photonic crystal cavity, utilizing a master equation to describe the system dynamics. To account for exciton-phonon interactions, we incorporate a non-perturbative approach through a polaron transformed master equation. By analyzing fluctuations in the Hermitian operators associated with relative and average phase, we derive a Fokker-Planck equation to assess phase drift and diffusion coefficients, demonstrating that correlated emission suppresses quantum noise in the presence of exciton-phonon interaction at low temperature. Additionally, we calculate the single and two-photon excess emission rates (difference between emission and absorption rates) into the cavity modes and explore the generation of continuous-variable entanglement between these modes.

quant-ph↗

arXiv2024

Cooperative two-photon lasing in two Quantum Dots embedded inside Photonic microcavity

We propose cooperative two-photon lasing in two quantum dots coupled to a single mode photonic crystal cavity. We consider both quantum dots are driven either incoherently or coherently using external pump. We incorporate exciton-phonon coupling using polaron transformed master equation. Using quantum laser theory, single and multi-photon excess emission (difference between emission and absorption) into cavity mode are investigated. The single and two-photon excess emission contribute to cavity photons, predominantly. Varying the pump strength can lead to single-photon excess emission change from negative to positive and thus by appropriately selecting pump strength single-photon excess emission can be made negligible.

quant-ph↗