arXiv subjects

Edgar A. Gómez

Publications and source records attributed to Edgar A. Gómez.

9 recordsLinked to original sources

arXiv2025

Control Protocol for Dynamic Synthesis of Qubit and Qudit Gates Using Photonic Pulses and Magnetic Fields

We propose a theoretical control protocol designed for the dynamic synthesis of single qubit and four-level qudit quantum gates using external parameters, such as photonic Gaussian pulses and magnetic fields, in a microcavity quantum well system. Our approach takes advantage of tunable coherent light matter interactions that can be modulated by the magnetic field between the exciton and negative trion coupled to the lowest photonic mode. We demonstrate that it is possible to achieve precise manipulation of populations of encoded quantum states through the unitary evolution of the system. In particular, we illustrate our optimization method for generating a single qubit gate with a mean fidelity of 99.99 as well as the realization of an iSWAP gate in the four level qudit case with a fidelity of 99.6.

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arXiv2020

Formation of spectral triplets induced by parity deformation in a quantum dot-cavity system

In this work, we conduct an investigation on the optical emission properties of a pumped-dissipative QD-cavity system within the Lindblad master equation approach, where the cavity mode is modeled through the R-deformed realization of the Heisenberg algebra (RDHA). We found that the parity deformation parameter associated with the RDHA gives rise to a collective phenomenon by reordering the one-photon optical transitions of the system, and it is demonstrated that there are two critical values for this parameter where a new type of spectral triplet arises in the emission spectrum. Moreover, our results reveal that depending on the critical value of the deformation parameter, the spectral triplets observed in the emission spectrum exhibit signatures of the weak- and strong-coupling regimes simultaneously.

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arXiv2019

Pure dephasing vs. Phonon mediated off-resonant coupling in a quantum-dot-cavity system

Pure dephasing is widely used in the literature to explain experimental observations on quantum dots in cavities. In many cases, its use is not enough and extra terms need to be "fictitiously" added to accomplish with the observed data as it is the case of cavity pumping of an unknown source. Here we controvert the validity of the pure dephasing mechanism as a source of decoherence and present a theoretical study based on the phonon-mediated coupling that can explain the emission spectrum and photon auto- and cross-correlation results in recent experiments without the need of any artificial assumptions. We also demonstrated that the phonon-mediated coupling accounts for unexplained features recently reported in measurements of photon auto- and cross-correlation functions. Our work illuminates many of the debates in this field and opens up new possibilities for experimental verification and theoretical predictions.

cond-mat.mes-hall↗

arXiv2019

Impact of a topological defect and Rashba spin-orbit interaction on the thermo-magnetic and optical properties of a 2D semiconductor quantum dot with Gaussian confinement

In this paper, we examine the effect of introducing a conical disclination on the thermal and optical properties of a two dimensional GaAs quantum dot in the presence of a uniform and constant magnetic field. In particular, our model consists of a single-electron subject to a confining Gaussian potential with a spin-orbit interaction in the Rashba approach. We compute the specific heat and the magnetic susceptibility from the exact solution of the Schrödinger equation via the canonical partition function, and it is shown that the peak structure of the Schottky anomaly is linearly displaced as a function of the topological defect. We found that such defect and the Rashba coupling modify the values of the temperature and magnetic field in which the system behaves as a paramagnetic material. Remarkably, the introduction of a conical disclination in the quantum dot relaxes the selection rules for the electronic transitions when an external electromagnetic field is applied. This creates a new set of allowed transitions causing the emergence of semi-suppressed resonances in the absorption coefficient as well as in the refractive index changes which are blue-shifted with respect to the regular transitions for a quantum dot without the defect.

cond-mat.mes-hall↗

arXiv2018

A comparative study on different non-Hermitian approaches for modeling open quantum systems

In this paper, we test and compare the performance of two different theoretical methods that use anti-Hermitian terms for modeling open quantum systems. It is, the non-Hermitian quantum mechanics method (NHQM) and the recent methodology known as corrected non-Hermitian effective Hamiltonian (corrected NHEH) approach. In particular, we provide a comprehensive analysis of the performance of these two theoretical approaches by describing the dynamics of the pumped-dissipative Jaynes--Cummings model. Our results demonstrate that whereas the NHQM method fails for describing correctly the time evolution of the density matrix elements as well as the quantum fidelity measure. The corrected NHEH approach shows an excellent agreement with simulations based on the Lindblad master equation formalism.

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arXiv2018

The strange attraction phenomenon in cQED: the intermediate quantum coupling regime

We theoretically investigate the strange phenomenon of attraction between the cavity mode and the exciton mode that has been experimentally observed in a photonic crystal cavity. Our results within the Lindblad master equation approach successfully explain why the apparent cavity-to-exciton spectral shifting occurs, and how this phenomenon is a manifestation of a dynamical phase transition in the system. Moreover, our findings are in good qualitative agreement with pioneer experimental results as well as support the hypothesis that an intermediate coupling regime exists in the cavity quantum electrodynamics. In fact, this new quantum regime exhibits phenomenology from both weak and strong coupling regimes simultaneously.

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arXiv2017

Explanation of the intriguing quantum phenomenon of the off-resonant cavity mode emission

We theoretically investigate the unexpected occurrence of an extra emission peak that has been experimentally observed in off-resonant studies of cavity QED systems. Our results within the Markovian master equation approach successfully explain why the central peak arises, and how it reveals that the system is suffering a dynamical phase transition induced by the phonon-mediated coupling. Our findings are in perfect agreement with previous reported experimental results and for the first time the fundamental physics behind this quantum phenomenon is understood.

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arXiv2017

A comparative study on heat capacity, magnetization and magnetic susceptibility for a GaAs quantum dot with asymmetric confinement

In this work, thermal and magnetic properties for an electron with cylindrical confinement in presence of external electric and magnetic fields have been investigated. We found that the corresponding time-independent Schrödinger equation can be separated into the product of the radially symmetric and an axial equation. Moreover, we have obtained a quasi-exact expression for the energy spectrum of the system in terms of the exact solutions for the radial equation and an approximation up to first order for the axial equation. We have calculated the well-known thermal and magnetic properties as the heat capacity, magnetization and the magnetic susceptibility via the canonical partition function. We found that our results for thermal and magnetic properties differ significantly from results previously obtained by others authors (by Gumber et. al.). Moreover, our results are in agreement with the diamagnetic properties of GaAs.

cond-mat.mes-hall↗

arXiv2009

Bose-Einstein condensates on tilted lattices: coherent, chaotic and subdiffusive dynamics

The dynamics of a (quasi)one-dimensional interacting atomic Bose-Einstein condensate in a tilted optical lattice is studied in a discrete mean-field approximation, i.e., in terms of the discrete nonlinear Schrödinger equation. If the static field is varied the system shows a plethora of dynamical phenomena. In the strong field limit we demonstrate the existence of (almost) non-spreading states which remain localized on the lattice region populated initially and show coherent Bloch oscillations with fractional revivals in the momentum space (so called quantum carpets). With decreasing field, the dynamics becomes irregular, however, still confined in configuration space. For even weaker fields we find sub-diffusive dynamics with a wave-packet width spreading as $t^{1/4}$.

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