Chinese Physics Letters

Quantum Zeno Effect Induced by Quantum Measurement of Momentum of Atomic Mass Center

Wang Xiaoguang

Published Dec 1, 1995• 3 citations

Abstract

In this article, we obtained the factorization form of the evolution operator corresponding to the Hamiltonian which describes the interaction of a two-level atom with one propagating mode in an optical ring cavity and the exact solution is followed. A new scheme for realizing quantum Zeno effect is proposed by measuring the atomic momentum (external state) frequently to freeze the atomic energy state (internal state) in its initial energy state.

DOI: 10.1088/0256-307x/12/12/007

Related papers

Quantum Zeno effect induced by quantum-nondemolition measurement of photon number

M. J. Gagen, Gerard J Milburn

Measurements performed on a system will alter the dynamics of that system, and in the strong-measurement limit, can theoretically freeze the free evolution completely. This is the quantum Zeno effect. We utilize quantum-nondemolition photon-counting techniques to realize the Zeno effect on the evolution of either a two-level Jaynes-Cummings atom interacting with a resonant cavity mode, or on two electromagnetic modes configured as a multilevel parametric frequency converter. These systems interact with another electromagnetic cavity mode via a quadratic coupling system based on four-wave mixing and constructed so as to be a nondemolition measurement of the photon number. This mode is then coupled to the environment through the cavity mirrors. This measurement is shown to be a measurement of system populations, which generates the desired Zeno effect and in the strong-measurement limit will freeze the free dynamics of the system.

Physical Review AApr 1, 199217 citations

Quantum Zeno effect in atomic Bragg scattering

Sigurd Dyrting, M. J. Gagen

We propose an experiment to observe the quantum Zeno effect in atomic Bragg scattering. The quantum Zeno effect is the inhibition of the free evolution of a system when that system is subject to a decohering measurement process. This effect is usually studied theoretically in an idealized two-level system, though this system has been difficult to realize in practice. The coherent population exchange between the forward and Bragg beams provides an ideal two-level system, though as there is no practical scheme for continuously monitoring the motion of an atom we include decoherence by adding noise to the laser. Using the method of stochastic Hamiltonians we show that the noise suppresses tunneling in the two-state system and, in the large noise limit, the system can freeze in its initial state.

Physical Review AAug 1, 19974 citations

Rydberg-atom phase-sensitive detection and the quantum Zeno effect

Gerard J Milburn, M. J. Gagen

We present a scheme for experimentally observing the quantum Zeno effect using the quantum-nondemolition measurement recently proposed by Brune et al. [Phys. Rev. Lett. 65, 976 (1990)]. The Zeno effect refers to the freezing of the (unitary) free dynamics of a system by rapid measurements. We generalize the Zeno effect to be any change in the survival probability of an initial state induced by very rapid measurements, when such measurements are the dominant source of fluctuations in the system. We derive a master equation for the evolution of a cavity mode when the photon number is monitored by this method. This equation describes a phase-diffusion process. We propose that this measurement scheme be used to monitor the exchange of a single photon between the cavity and a single Rydberg atom. We show that for very rapid monitoring the free oscillation of the atomic inversion is disrupted and the atom can be trapped close to the initial excited state. This is the quantum Zeno effect.

Physical Review AAug 1, 199220 citations

Quantum Zeno Effect and Atomic Population Inversion

Jiuming Li

Quantum Zeno effect can be applied to quantum information processing，and can reveal the nature of quantum measurement. In addition, it has also many potential applications. This suggests that studying the quantum Zeno effect has great theoretical and experimental significance. In this work, the system of a two-level atom interacting with a single mode field is considered and the dynamics of the system subjected to successive projection measurements is studied, and the quantum Zeno effect is presented. Moreover, the influence of the quantum Zeno effect on atomic population inversion is discussed. Based on Schrödinger equation, the survival probability of the initial state of the two-level atom subjected to frequently repeated measurements can be obtained. The survival probability depends on the time interval between measurements. It is seen that the exponential decay of the system under slowly frequent measurements is presented instead of the naturally oscillatory process. For slowly repeated measurements the atomic population inversion and the survival probability of initial state decline rapidly at the early time and then both of them become unchanged. As the time intervals of the measurements are sufficiently short, the quantum Zeno effect occurs. These results have also shown how the measurement can inhibit the atomic population inversion.

American Journal of Modern PhysicsJan 1, 20180 citations

The Quantum Zeno Capacity and Dynamic Evolution Mode of a Quantum System

Zhenbo Ni, Yonggang Peng, Yujun Zheng

The quantum Zeno effect (QZE) is widely employed in quantum engineering due to the issue of frequent measurements freezing a quantum system. In this study, the quantum Zeno factor is introduced to characterize the quantum Zeno capacity of a quantum system. The quantum Zeno factor reveals that the quantum Zeno effect is dependent on the evolution mode of quantum states, which is semi-irrelevant to conventional energy uncertainty and extends the QZE domain. The Zeno factor provides a new consideration to qualify the (anti-)Zeno capacity of a quantum system for its applications: a large quantum Zeno factor value indicates that a quantum system is of a QZE quality. The numerical results of the quantum Zeno capacity are shown using two typical examples: tailing the dynamic evolution modes using the quantum Zeno factor in a three-level system, and quantifying the message exchange between qubits in a coupled qubit system using a quantum Zeno factor.

EntropyDec 11, 20242 citations

Quantum Zeno dynamics: mathematical and physical aspects

Paolo Facchi A, Saverio Pascazio

Abstract. If frequent measurements ascertain whether a quantum system is still in its initial state, transitions to other states are hindered and the quantum Zeno effect takes place. However, in its broader formulation, the quantum Zeno effect does not necessarily freeze everything. On the contrary, for frequent projections onto a multidimensional subspace, the system can evolve away from its initial state, although it remains in the subspace defined by the measurement. The continuing time evolution within the projected “quantum Zeno subspace ” is called “quantum Zeno dynamics: ” for instance, if the measurements ascertain whether a quantum particle is in a given spatial region, the evolution is unitary and the generator of the Zeno dynamics is the Hamiltonian with hard-wall (Dirichlet) boundary conditions. We discuss the physical and mathematical aspects of this evolution, highlighting the open mathematical problems. We then analyze some alternative strategies to obtain a Zeno dynamics and show that they are physically equivalent.

Nov 20, 2012336 citations