Decoherence without dissipation due to fermionic bath

Karmakar, Anirban; Gangopadhyay, Gautam

doi:10.1088/0031-8949/85/04/045008

Cited by 12 publications

(24 citation statements)

References 45 publications

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“…where c ± + are the fermionic creation/annihilation operators on the positive helicity mode (c + = |∅ 1 k,+ | and c + + = |1 k,+ ∅|),n = and γ characterizes the spectral density of the bath. With some assumptions γ(1 −n) ≃ γ0ω 4kB T where γ 0 is a constant (see [28]). Sincen is very small (the Unruh temperature T is very small), the master equation is dominated by the dissipation of |1 k,+ = |φ + in accordance with eq.…”

Section: Rindler Spacetimementioning

confidence: 99%

“…For the positive helicity mode (which is the part of the Weyl spinor with positive energy), we can write that the density matrix ρ + (for |1 k,+ = |φ + and |∅ ) obeys to the master equation (see for example [27]): and γ characterizes the spectral density of the bath. With some assumptions γ(1 − n) ≃ γ0ω 4kB T where γ 0 is a constant (see [28]). Since n is very small (the Unruh temperature T is very small), the master equation is dominated by the dissipation of |1 k,+ = |φ + in accordance with eq.…”

Section: Rindler Spacetimementioning

confidence: 99%

“…where CNOT A and H A are the CNOT and Hadamard gates in Alice's frame. After some algebra, we find where γ 0 is a constant (see [28]). Since n is very small (the Unruh temperature T is very small), the master equation is dominated by the dissipation of…”

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confidence: 99%

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Adiabatic transport of qubits around a black hole

Viennot

Moro

2017

Class. Quantum Grav.

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We consider localized qubits evolving around a black hole following a quantum adiabatic dynamics. We develop a geometric structure (based on fibre bundles) permitting to describe the quantum states of a qubit and the spacetime geometry in a single framework. The quantum decoherence induced by the black hole on the qubit is analysed in this framework (the role of the dynamical and geometric phases in this decoherence is treated), especially for the quantum teleportation protocol when one qubit falls to the event horizon. A simple formula to compute the fidelity of the teleportation is derived. The case of a Schwarzschild black hole is analysed.

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Section: Rindler Spacetimementioning

confidence: 99%

Section: Rindler Spacetimementioning

confidence: 99%

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Adiabatic transport of qubits around a black hole

Viennot

Moro

2017

Class. Quantum Grav.

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“…This reduction in the coupling will in turn act as a source to induce coherence within the system dynamics. The present authors [43] have already studied such effects in the context of a system coupled to a spin bath via a quantum non-demolition type of interaction. Here, it would not be out of place to mention that the asymptotic solution of Bloch equations can also be used in the study of quantum transport [44], and to study magnetization vector dynamics [45] and spin-current damping phenomena [46] in spin polarized Fermi liquids.…”

Section: The Master Equation and Asymptotic Solution Of A Modified Bl...mentioning

confidence: 99%

A fermionic bath induced antibunching and coherence in Mollow spectra

Karmakar¹,

Gangopadhyay²

2014

Phys. Scr.

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In this work, we have derived the modified Bloch equation from the generalized master equation due to the fermionic bath where one needs to consider Grassmann algebra to obtain the similar mathematical structure of the reduced system dynamics, as in the case of a bosonic bath. There is an enhancement of antibunching in the photon emission with an increase in effective temperature. This is in principle a manifestation of the antisymmetric two-particle dynamic anticorrelation in the fermionic bath with a defined chemical potential characterized by the forbidden overlapping. This is evident from the modified fluctuation–dissipation relation. We have compared it thoroughly with an experimental result in the temperature dependent emission characteristics within an environment of quantum dots in a Hanburry-Brown–Twiss set-up. For the fermionic bath, an effective temperature assisted coherence phenomenon is induced in the system dynamics, which is reflected in the resonance fluorescence spectrum with the variation of chemical potential. In the Mollow's absorption spectra, when the Rabi frequency is sufficiently low, the side peaks appear as chemical potential induced coherence phenomenon rather than the traditional field induced one. The subsequent gain in the probe wave is evidently of thermal origin, where the energy is fully supplied by the fermionic bath at non-zero temperatures. This is not possible for a bosonic bath—an example of the extraction of coherence from the fermionic bath.

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“…The microscopic basis of quantum dissipation of open systems − are provided by the traditional bosonic description of the thermal reservoir which is useful in a wide variety of physical situations − such as, spontaneous emission, polaron formation, exciton motion, macroscopic quantum tunneling, energy transport to name a few. In the case of electron transport, a slight modification by accommodating a Fermionic character of the reservoir makes the dissipative and decoherence dynamics significantly different from that of the bosonic case . However, coupling of a quantum system with two reservoirs to study electron transport dynamics for a molecular system follows a standard paradigm. − In spite of a great deal of theoretical and experimental investigations in the context of electron transport through systems, − physical insights about coherent dynamics of entangled electron–vibration motion in molecules are very limited in this context.…”

Section: Introductionmentioning

confidence: 99%

Electron–Vibration Entanglement of Resonating Dimers in Quantum Transport

Karmakar¹,

Gangopadhyay

2021

J. Phys. Chem. A

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Electron transport in a single molecule resulting from the superposition of its vibronic states depends on the coupling strength with the metallic leads. However, dynamical coherence and Fermionic correlation in molecule−molecule and molecule−lead coupling necessitates a critical approach to treat the current and its noise level, especially in the presence of a variable external bias for temperature-dependent conduction. Primarily, this work is a generalization of the theoretical approach of the atomic dimers to incorporate the effect of vibrational modes in current and conductance characteristics. The variation of current and differential conductance due to the external bias reveals a vibrational Coulomb blockade structure corresponding to the functioning vibrational mode in the system. The numerical demonstration for a diverse class of molecules generically shows that electron−vibration interaction can quantitatively predict the nature of coherent electron transport and current noise. Secondly, an attempt has been made to illustrate the effect of magnitude of coherence-induced noise suppression of current as a signature of electron−vibration entanglement. Finally, temperature-dependent conductance of the molecular junction in dimer structure has been estimated along with the peak shifts due to the applied gate voltage.

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Decoherence without dissipation due to fermionic bath

Cited by 12 publications

References 45 publications

Adiabatic transport of qubits around a black hole

Adiabatic transport of qubits around a black hole

A fermionic bath induced antibunching and coherence in Mollow spectra

Electron–Vibration Entanglement of Resonating Dimers in Quantum Transport

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