Three Different Manifestations of the Quantum Zeno Effect

Facchi, Paolo; Pascazio, Saverio

doi:10.1007/3-540-44874-8_7

Cited by 10 publications

(15 citation statements)

References 41 publications

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“…This is only a specific manifestation of quantum Zeno effect. In fact, it can be manifested in a few equivalent ways [6]. One such manifestation of quantum Zeno effect is a process in which continuous interaction between the system and probe leads * Email: anirban.pathak@gmail.com, Phone: +91 9717066494 to quantum Zeno effect.…”

Section: Introductionmentioning

confidence: 99%

Linear and nonlinear quantum Zeno and anti-Zeno effects in a nonlinear optical coupler

2016

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Quantum Zeno and anti-Zeno effects are studied in a symmetric nonlinear optical coupler, which is composed of two nonlinear (χ (2) ) waveguides that are interacting with each other via the evanescent waves. Both the waveguides operate under second harmonic generation. However, to study quantum Zeno and anti-Zeno effects one of them is considered as the system and the other one is considered as the probe. Considering all the fields involved as weak, a completely quantum mechanical description is provided, and the analytic solutions of Heisenberg's equations of motion for all the field modes are obtained using a perturbative technique. Photon number statistics of the second harmonic mode of the system is shown to depend on the presence of the probe, and this dependence is considered as quantum Zeno and anti-Zeno effects. Further, it is established that as a special case of the momentum operator for χ (2) − χ (2) symmetric coupler we can obtain momentum operator of χ (2) − χ (1) asymmetric coupler with linear (χ (1) ) waveguide as the probe, and in such a particular case, the expressions obtained for Zeno and anti-Zeno effects with nonlinear probe (which we referred to as nonlinear quantum Zeno and anti-Zeno effects) may be reduced to the corresponding expressions with linear probe (which we referred to as the linear quantum Zeno and anti-Zeno effects). Linear and nonlinear quantum Zeno and anti-Zeno effects are rigorously investigated, and it is established that in the stimulated case, we may switch between quantum Zeno and anti-Zeno effects just by controlling the phase of the second harmonic mode of the system or probe.

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Section: Introductionmentioning

confidence: 99%

Linear and nonlinear quantum Zeno and anti-Zeno effects in a nonlinear optical coupler

2016

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“…This kind of continuous interaction with an external system is equivalent to the original inhibition or enhancement of evolution of the system on continuous measurement as measurement is strong coupling with a measuring device. [27][28][29] An important example of nonlinear optical coupler is an asymmetric nonlinear optical coupler, consisting of a nonlinear waveguide with χ (2) nonlinearity operating under second harmonic generation coupled with a linear waveguide. This system is studied earlier and the nonclassical properties (such as squeezing, antibunching and entanglement) have been reported in this system for both codirectional and contradirectional propagation of the field in the linear waveguide ( [30][31][32][33] and references therein).…”

Section: Introductionmentioning

confidence: 99%

Quantum Zeno and anti-Zeno effects in an asymmetric nonlinear optical coupler

Thapliyal

Pathak

2015

SPIE Proceedings

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Quantum Zeno and anti-Zeno eects in an asymmetric nonlinear optical coupler are studied. The asymmetric nonlinear optical coupler is composed of a linear waveguide (χ (1) ) and a nonlinear waveguide (χ (2) ) interacting with each other through the evanescent waves. The nonlinear waveguide has quadratic nonlinearity and it operates under second harmonic generation. A completely quantum mechanical description is used to describe the system. The closed form analytic solutions of Heisenberg's equations of motion for the dierent eld modes are obtained using Sen-Mandal perturbative approach. In the coupler, the linear waveguide acts as a probe on the system (nonlinear waveguide). The eect of the presence of the probe (linear waveguide) on the photon statistics of the second harmonic mode of the system is considered as quantum Zeno and anti-Zeno eects. Further, it is also shown that in the stimulated case, it is easy to switch between quantum Zeno and anti-Zeno eects just by controlling the phase of the second harmonic mode of the asymmetric coupler.

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“…Building on techniques previously used to study unitary Zeno dynamics [58][59][60][61], we here apply it in a very different context: in the temperature domain and generalized to open systems which requires carrying out a highly nontrivial trace over the reservoir. Importantly, we show that all diverging terms with positive powers of λ cancel.…”

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confidence: 99%

Weak and Ultrastrong Coupling Limits of the Quantum Mean Force Gibbs State

Cresser

Anders

2021

Phys. Rev. Lett.

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The Gibbs state is widely taken to be the equilibrium state of a system in contact with an environment at temperature T. However, non-negligible interactions between system and environment can give rise to an altered state. Here, we derive general expressions for this mean force Gibbs state, valid for any system that interacts with a bosonic reservoir. First, we derive the state in the weak coupling limit and find that, in general, it maintains coherences with respect to the bare system Hamiltonian. Second, we develop a new expansion method suited to investigate the ultrastrong coupling regime. This allows us to derive the explicit form for the mean force Gibbs state, and we find that it becomes diagonal in the basis set by the systemreservoir interaction instead of the system Hamiltonian. Several examples are discussed including a single qubit, a three-level V-system, and two coupled qubits all interacting with bosonic reservoirs. The results shed light on the presence of coherences in the strong coupling regime, and provide key tools for nanoscale thermodynamics investigations.

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Three Different Manifestations of the Quantum Zeno Effect

Cited by 10 publications

References 41 publications

Linear and nonlinear quantum Zeno and anti-Zeno effects in a nonlinear optical coupler

Linear and nonlinear quantum Zeno and anti-Zeno effects in a nonlinear optical coupler

Quantum Zeno and anti-Zeno effects in an asymmetric nonlinear optical coupler

Weak and Ultrastrong Coupling Limits of the Quantum Mean Force Gibbs State

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