Quantum coherence of critical unstable two-level systems

Karamitros, Dimitrios; T., McKelvey,; Pilaftsis, Apostolos

doi:10.1103/physrevd.108.016006

Cited by 4 publications

(1 citation statement)

References 20 publications

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“…Recently, the QC has been used to reveal the nonclassical characteristics of various systems. Involving superinductors [36], two-level molecular system [37], polariton condensates [38], critical unstable two-level systems [39], quantum dot systems [40], cavity magnomechanical systems [41], quantum batteries [42], neutrino [43], linear systems of equations [44], dipolar interacting magnetic system [45], Heisenberg model [46], noninertial frame [47], and spacetime expansion [48]. Besides, reservoir system is significant for quantum information [49], and the transformation between coherence and entanglement of reservoir system was revealed by Hu et al [50].…”

Section: Introductionmentioning

confidence: 99%

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

Xing,

Yang,

Kong

et al. 2024

Phys. Scr.

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The nonlocal advantage of quantum coherence (NAQC), quantum coherence (QC), and quantum entanglement are promising quantum resources to achieve various quantum information tasks. However, the decoherence of quantum resource is detrimental to the implementation of quantum information processing, and it brings enormous challenge to the application of quantum resource. Here, consider that Alice and Bob possess a two-qubit X state, and the two-qubit X state is composed of two atoms. Bob’s atom interacts with a reservoir, and Alice’s atom is subjected to the inﬂuence of amplitude damping channel. We design an eﬀective scheme by coupling auxiliary qubits with reservoir, and this scheme can signiﬁcantly suppress the dissipation of the NAQC, QC, and quantum entanglement. The results reveal that the NAQC, QC, and quantum entanglement degenerate with the increase of time t in the strong coupling regime or weak coupling regime when absenting auxiliary qubits. If one adds some auxiliary qubits in the reservoir, these quantum resources can be strengthened both in the strong coupling regime and weak coupling regime. Auxiliary qubits can help us eﬀectively resist the dissipation of these quantum resources. In comparison with the QC and quantum entanglement, the NAQC is most fragile and it is most vulnerable to the inﬂuences of reservoir and noise channel. One needs introduce more auxiliary qubits to suppress the dissipation of the NAQC, especially in the scenarios of the weak coupling regime and strong channel parameter. In this sense, our investigations may provide a potent technique for restraining decoherence and oﬀer a new platform for quantum resource application.

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Section: Introductionmentioning

confidence: 99%

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

Xing,

Yang,

Kong

et al. 2024

Phys. Scr.

View full text Add to dashboard Cite

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Effective field theory of particle mixing

Cao,

Boyanovsky

2024

Phys. Rev. D

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We introduce an effective field theory to study mixing of two fields induced by their couplings to a common decay channel in a medium. The extension of the method of Lee, Oehme, and Yang, the cornerstone of analysis of CP violation in flavored mesons, to include the mixing of particles with different masses provides a guide to and benchmark for the effective field theory. The analysis reveals subtle caveats in the description of mixing in terms of the widely used non-Hermitian effective Hamiltonian, more acute in the nondegenerate case. The effective field theory describes the dynamics of field mixing where the common intermediate states populate a bath in thermal equilibrium, as an . We obtain the effective action up to second order in the couplings, where indirect mixing is a consequence of off-diagonal self-energy components. We find that if only one of the mixing fields features an initial expectation value, indirect mixing induces an expectation value of the other field. The equal time two point correlation functions exhibit an asymptotic approach to a stationary thermal state, and the emergence of long-lived coherence which displays quantum beats as a consequence of interference of quasinormal modes in the medium. The amplitudes of the quantum beats are resonantly enhanced in the nearly degenerate case with potential observational consequences. Published by the American Physical Society 2024

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Varying entropy degrees of freedom effects in low-scale leptogenesis

Karamitros,

McKelvey,

Pilaftsis

2024

Phys. Rev. D

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We analyze in detail the effect of varying entropy degrees of freedom on low-scale leptogenesis models. As an archetypal model, we consider the triresonant leptogensis (TRL) scenario introduced recently by the authors, where the neutrino-Yukawa coupling matrix is dictated by an approximate Zn discrete symmetry (with n=3, 6). TRL models exhibit no preferred direction in the leptonic flavor space and have the remarkable feature that leptogenesis can successfully take place even if all light neutrinos are strictly massless up to one-loop order. Most interestingly, for TRL scenarios with heavy Majorana neutrinos lighter than 100 GeV, temperature varying degrees of freedom associated with the entropy of the plasma have a dramatic impact on the predictions of the baryon asymmetry in the Universe (BAU), and may depend on the freeze-out sphaleron temperature Tsph. We find that this is a generic feature of most freeze-out low-scale leptogenesis models discussed in the literature. In the same context, we consider heavy-neutrino scenarios realizing dynamics related to critical unstable qudits in the thermal plasma and assess their significance in generating the BAU. The phenomenological implications of TRL scenarios at the intensity and high-energy frontiers are analyzed. Published by the American Physical Society 2024

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Quantum coherence of critical unstable two-level systems

Cited by 4 publications

References 20 publications

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

Suppressing the degeneration of quantum resources through coupling auxiliary qubits

Effective field theory of particle mixing

Varying entropy degrees of freedom effects in low-scale leptogenesis

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