Quantum Zeno Effect Induced by Collisions

Nagels, B.; Hermans, L. J. F.; Chapovsky, P. L.

doi:10.1103/physrevlett.79.3097

Cited by 67 publications

(56 citation statements)

References 14 publications

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“…Previous demonstrations of the continuous QZE [3,4,6] observed qualitative, but not quantitatively characterized QZE suppression effects up to 80% [4] with increasing laser intensity. Our observed quantum Zeno suppressions are substantially larger then both previous pulsed [2] and continuous [4] results, and is also greater then that expected from proposed experiments [11,15,26,28] in neutrons.…”

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confidence: 99%

“…Experimental demonstrations of the QZE [2,3,4,5,6,7,8] have been driven by interest in both fundamental physics and practical applications. Practical applications of the QZE include reducing decoherence in quantum computing [8,9,10], efficient preservation of spin polarized gases [3,4,6], and dosage reduction in neutron tomography [11].The QZE is a paradigm and test bed for quantum measurement theory [12,13]. In one interpretation, it involves many sequential collapses of the wavefunctions of the system.…”

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confidence: 99%

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Continuous and Pulsed Quantum Zeno Effect

Streed¹,

Mun²,

Boyd³

et al. 2006

Phys. Rev. Lett.

178

186

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Continuous and pulsed quantum Zeno effects were observed using a 87 Rb Bose-Einstein condensate (BEC). Oscillations between two ground hyperfine states of a magnetically trapped condensate, externally driven at a transition rate ωR, were suppressed by destructively measuring the population in one of the states with resonant light. The suppression of the transition rate in the two level system was quantified for pulsed measurements with a time interval δt between pulses and continuous measurements with a scattering rate γ. We observe that the continuous measurements exhibit the same suppression in the transition rate as the pulsed measurements when γδt = 3.60(0.43), in agreement with the predicted value of 4. Increasing the measurement rate suppressed the transition rate down to 0.005ωR.PACS numbers: 03.65. Xp,03.75.Mn,42.50.Xa The quantum Zeno effect (QZE) is the suppression of transitions between quantum states by frequent measurements. It was first considered as a theoretical problem where the continuous observation of an unstable particle would prevent its decay [1]. Experimental demonstrations of the QZE [2,3,4,5,6,7,8] have been driven by interest in both fundamental physics and practical applications. Practical applications of the QZE include reducing decoherence in quantum computing [8,9,10], efficient preservation of spin polarized gases [3,4,6], and dosage reduction in neutron tomography [11].The QZE is a paradigm and test bed for quantum measurement theory [12,13]. In one interpretation, it involves many sequential collapses of the wavefunctions of the system. Quantum Zeno experiments provide constraints for speculative extensions of quantum mechanics where the collapse of the wavefunction is created by extra terms in a modified Schrödinger equation [14]. It is still an open question how close one can approach the limit of an infinite number of interrogations due to the Heisenberg uncertainty involved in shorter measurement times. These conceptional questions provide the motivation to extend experimental tests of the quantum Zeno phenonmenon. A major improvement to a quatum Zeno experiment with ultracold neutrons [15] is in preparation.In this letter we compare the suppression of the transition rate in an oscillating two level system by continuous and pulsed measurements. Our QZE experiments were carried out with Bose-Einstein condensed atoms [16,17,18]. The long coherence time and the high degree of control of the position and momentum of the atoms created a very clean system and allowed us to observe much stronger quantum Zeno suppression than before [2,5,7]. In the experiment with pulsed measurements up to 500 measurements could be carried out and survival probabilities exceeded 98%. Furthermore, we have performed the first quantitative comparison between the pulsed and continuous measurement QZE. This is important since any real pulsed measurement is only an approximation based on a series of weak continuous measurements [19,20].Let us consider a two-level system which is externally driven at a ...

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confidence: 99%

mentioning

confidence: 99%

Continuous and Pulsed Quantum Zeno Effect

Streed¹,

Mun²,

Boyd³

et al. 2006

Phys. Rev. Lett.

178

186

View full text Add to dashboard Cite

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“…Quantum Zeno effects appear in several physical systems, some of which are very similar to radical-ion-pairs, like the ortho-para conversion in molecular spin isomers [27], ultra-cold atom tunneling through optical potentials [28], or the suppression of transverse spin-relaxation due to spin-exchange collisions in dense alkali-metal vapors [29,30]. In the latter case, atomic spin-exchange collisions, of the form s 1 · s 2 , where s 1 and s 2 are the electron spins of the two colliding atoms, probe the atomic spin state.…”

Section: Phenomenological Master Equationmentioning

confidence: 99%

Quantum Zeno effect explains magnetic-sensitive radical-ion-pair reactions

Kominis

2009

Phys. Rev. E

108

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Chemical reactions involving radical-ion pairs are ubiquitous in biology, since not only are they at the basis of the photosynthetic reaction chain, but are also assumed to underlie the biochemical magnetic compass used by avian species for navigation. Recent experiments with magnetic-sensitive radical-ion pair reactions provided strong evidence for the radical-ion-pair magnetoreception mechanism, verifying the expected magnetic sensitivities and chemical product yield changes. It is here shown that the theoretical description of radical-ion-pair reactions used since the 70's cannot explain the observed data, because it is based on phenomenological equations masking quantum coherence effects. The fundamental density matrix equation derived here from basic quantum measurement theory considerations naturally incorporates the quantum Zeno effect and readily explains recent experimental observations on low-and high-magnetic-field radical-ion-pair reactions.

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“…QZE and QAZE have attracted much attention since they were proposed. So far the two effects have been experimentally observed in the systems of trapped ions [4,5], ultracold atoms [6][7][8], molecules [9] and cavity quantum electric dynamics (cavity QED) [10].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of quantum zeno and anti-zeno effects in an open system

Zhang

et al. 2014

Sci. China Phys. Mech. Astron.

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We provide a general dynamical approach for the quantum Zeno and anti-Zeno effects in an open quantum system under repeated non-demolition measurements. In our approach the repeated measurements are described by a general dynamical model without the wave function collapse postulation. Based on that model, we further study both the short-time and long-time evolutions of the open quantum system under repeated non-demolition measurements, and derive the measurementmodified decay rates of the excited state. In the cases with frequent ideal measurements at zerotemperature, we re-obtain the same decay rate as that from the wave function collapse postulation (Nature 405, 546 (2000)). The correction to the ideal decay rate is also obtained under the nonideal measurements. Especially, we find that the quantum Zeno and anti-Zeno effects are possibly enhanced by the non-ideal natures of measurements. For the open system under measurements with arbitrary period, we generally derive the rate equation for the long-time evolution for the cases with arbitrary temperature and noise spectrum, and show that in the long-time evolution the noise spectrum is effectively tuned by the repeated measurements. Our approach is also able to describe the quantum Zeno and anti-Zeno effects given by the phase modulation pulses, as well as the relevant quantum control schemes.

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Quantum Zeno Effect Induced by Collisions

Cited by 67 publications

References 14 publications

Continuous and Pulsed Quantum Zeno Effect

Continuous and Pulsed Quantum Zeno Effect

Quantum Zeno effect explains magnetic-sensitive radical-ion-pair reactions

Dynamics of quantum zeno and anti-zeno effects in an open system

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