Quantum metrology in local dissipative environments

Wang, Yuansheng; Chen, Chong; An, Jing

doi:10.1088/1367-2630/aa8b01

Cited by 33 publications

(26 citation statements)

References 67 publications

(130 reference statements)

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“…Many of these studies are typically concerned with estimating the frequency ω rather than the phase f; the two parameters are related to each other by the encoding time t, i.e., f=ω t. Thus, the total running time of the encoding process itself is regarded as a resource [13]. These studies have shown that a super-extensive growth of the frequency sensitivity may still be attained under time-inhomogeneous, phase-covariant noise [26][27][28][29][30], and even more generic Ohmic dissipation [31], noise with a particular geometry [32,33], or setups related to quantum error correction [34][35][36]. See also [37,38] which question the role of entanglement in such schemes and give advice on practical implementations.…”

Section: Introductionmentioning

confidence: 99%

Noisy frequency estimation with noisy probes

et al. 2018

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We consider frequency estimation in a noisy environment with noisy probes. This builds on previous studies, most of which assume that the initial probe state is pure, while the encoding process is noisy, or that the initial probe state is mixed, while the encoding process is noiseless. Our work is more representative of reality, where noise is unavoidable in both the initial state of the probe and the estimation process itself. We prepare the probe in a GHZ diagonal state, starting from n+1 qubits in an arbitrary uncorrelated mixed state, and subject it to parameter encoding under dephasing noise. For this scheme, we derive a simple formula for the (quantum and classical) Fisher information, and show that quantum enhancements do not depend on the initial mixedness of the qubits. That is, we show that the so-called 'Zeno' scaling is attainable when the noise present in the encoding process is time inhomogeneous. This scaling does not depend on the mixedness of the initial probe state, and it is retained even for highly mixed states that can never be entangled. We then show that the sensitivity of the probe in our protocol is invariant under permutations of qubits, and monotonic in purity of the initial state of the probe. Finally, we discuss two limiting cases, where purity is either distributed evenly among the probes or concentrated in a single probe.

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Section: Introductionmentioning

confidence: 99%

Noisy frequency estimation with noisy probes

et al. 2018

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“…It has been reported that such a bound state has profound impacts on many quantum protocols and nonequilibrium physics, e.g. entanglement preservation [28][29][30], noncanonical thermalization [31], quantum speed limit [32], and quantum metrology [33][34][35]. The results give us an insightful guideline to control decoherence via forming the bound state by quantum reservoir engineering [36,37].…”

Section: Introductionmentioning

confidence: 98%

Quantum control in open and periodically driven systems

Bai

Chen

et al. 2021

Advances in Physics: X

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Quantum technology resorts to efficient utilization of quantum resources to realize technique innovation. The systems are controlled such that their states follow the desired manners to realize different quantum protocols. However, the decoherence caused by the system-environment interactions causes the states deviating from the desired manners. How to protect quantum resources under the coexistence of active control and passive decoherence is of significance. Recent studies have revealed that the decoherence is determined by the feature of the system-environment energy spectrum: Accompanying the formation of bound states in the energy spectrum, the decoherence can be suppressed. It supplies a guideline to control decoherence. Such idea can be generalized to systems under periodic driving. By virtue of manipulating Floquet bound states in the quasienergy spectrum, coherent control via periodic driving dubbed as Floquet engineering has become a versatile tool not only in controlling decoherence, but also in artificially synthesizing exotic topological phases. We will review the progress on quantum control in open and periodically driven systems. Special attention will be paid to the distinguished role played by the bound states and their controllability via periodic driving in suppressing decoherence and generating novel topological phases.

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“…To deal with this issue, dynamical decoupling 5,25 , feedback control [26][27][28] and many other approaches have been developed. Moreover, non-Markovian effect is also shown to be effective to maintain entanglement-induced high measurement precision 29,30 . Most of the above works focus on how to prepare or protect entangled states for quantum metrology.…”

Section: Introductionmentioning

confidence: 99%

Quantum metrology enhanced by coherence-induced driving in a cavity-QED setup

2019

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Entangled states are beneficial for quantum metrology, but difficult to prepare and maintain. To tackle this issue, we here propose a quantum metrology scheme in a cavity QED setup to achieve the Heisenberg limit without preparing entangled states. In our scheme, a series of identical two-level atoms randomly pass through and interact with the cavity mode. We show that the initial atomic coherence will induce an effective driving to the cavity field, whose steady state is an incoherent superposition of orthogonal states, with the superposition probabilities being dependent on the atom-cavity coupling strength. By measuring the average photon number of the cavity in the steady state, we demonstrate that the root-mean-square of the fluctuation of the atom-cavity coupling strength is proportional to 1/N 2 c (N c is the effective atom number interacting with the photon in the cavity during its lifetime). It implies that we have achieved the Heisenberg limit in our quantum metrology process. We also discuss the experimental feasibility of our theoretical proposal. Our findings may find potential applications in quantum metrology technology.

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Quantum metrology in local dissipative environments

Cited by 33 publications

References 67 publications

Noisy frequency estimation with noisy probes

Noisy frequency estimation with noisy probes

Quantum control in open and periodically driven systems

Quantum metrology enhanced by coherence-induced driving in a cavity-QED setup

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