Estimating temperature via sequential measurements

Pasquale, Antonella De; Yuasa, Kazuya; Giovannetti, Vittorio

doi:10.1103/physreva.96.012316

Cited by 61 publications

(74 citation statements)

References 33 publications

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“…As already mentioned, it is necessary to optimise the Fisher information over the initial preparationˆ P (0) and the free evolution time t [178]. As it turns out, preparing the qubit in the ground stateˆ (0) = |g g| and measuring its energy at t = π/2λ maximises the FI, which also coincides with the maximum possible thermal sensitivity given by the QFI (see also references [32,38,40]). Other forms of probe system coupling yield similar results [183].…”

Section: Thermometry Under Non-thermalising Dynamicsmentioning

confidence: 96%

“…We thus see that the relevant figure of merit to be maximised is η T (t) F (t)/t, and not F (t) alone [193,194]. The largest η T (t) is attained at some temperature-dependent optimal interrogation time when the probe is reset to its ground state after every measurement [38,32,40,45] (see figure 13). This is indeed the case for two-level and harmonic probes, and holds for any spectral density, provided that it is consistent with the approximations invoked in the derivation of equation (71) [32].…”

Section: Thermometry Under Thermalising Dynamicsmentioning

confidence: 98%

“…It is interesting to compare F res c (n, t) with the FI of a sequential protocol in which the probe is not reset after each measurement [see figure 13(b)]. That is, when following each interrogation, the corresponding outcome is recorded and the the post-measurement state is left to evolve dissipatively until the next measurement [40]. We denote the FI of this sequential setting by F seq c (n, t).…”

Section: Thermometry Under Thermalising Dynamicsmentioning

confidence: 99%

See 2 more Smart Citations

Thermometry in the quantum regime: recent theoretical progress

Mehboudi¹,

Sanpera²,

Correa³

2019

J. Phys. A: Math. Theor.

158

176

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Controlling and measuring the temperature in different devices and platforms that operate in the quantum regime is, without any doubt, essential for any potential application. In this review, we report the most recent theoretical developments dealing with accurate estimation of very low temperatures in quantum systems. Together with the emerging experimental techniques and developments of measurement protocols, the theory of quantum thermometry will decisively impinge and shape the forthcoming quantum technologies. While current quantum thermometric methods differ greatly depending on the experimental platform, the achievable precision, and the temperature range of interest, the theory of quantum thermometry is built under a unifying framework at the crossroads of quantum metrology, open quantum systems, and quantum many-body physics. At a fundamental level, theoretical quantum thermometry is concerned with finding the ultimate bounds and scaling laws that limit the precision of temperature estimation for systems in and out of thermal equilibrium. At a more practical level, it provides tools to formulate precise, yet feasible, thermometric protocols for relevant experimental architectures. Last but not least, the theory of quantum thermometry examines genuine quantum features, like entanglement and coherence, for their exploitation in enhanced-resolution thermometry.

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Section: Thermometry Under Non-thermalising Dynamicsmentioning

confidence: 96%

Section: Thermometry Under Thermalising Dynamicsmentioning

confidence: 98%

Section: Thermometry Under Thermalising Dynamicsmentioning

confidence: 99%

See 1 more Smart Citation

Thermometry in the quantum regime: recent theoretical progress

Mehboudi¹,

Sanpera²,

Correa³

2019

J. Phys. A: Math. Theor.

158

176

View full text Add to dashboard Cite

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“…In this paper, we address the use of quantum probes to estimate an emergent property of a complex system, i.e. its temperature [10][11][12][13][14][15]. In particular, in view of its importance for several fields of quantum information science, we consider here quantum thermometry of a bosonic bath in the Ohmic regime, ranging from sub-Ohmic to super-Ohmic.…”

Section: Introductionmentioning

confidence: 99%

Two-qubit quantum probes for the temperature of an Ohmic environment

et al. 2020

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We address a particular instance where open quantum systems may be used as quantum probes for an emergent property of a complex system, as the temperature of a thermal bath. The inherent fragility of the quantum probes against decoherence is the key feature making the overall scheme very sensitive. The specific setting examined here is that of quantum thermometry, which aims to exploits decoherence as resource to estimate the temperature of a sample. We focus on temperature estimation for a bosonic bath at equilibrium in the Ohmic regime (ranging from sub-Ohmic to super-Ohmic), by using pairs of qubits in different initial states and interacting with different environments, consisting either of a single thermal bath, or of two independent ones at the same temperature. Our scheme involves pure dephasing of the probes, thus avoiding energy exchange with the sample and the consequent perturbation of temperature itself. We discuss the interplay between correlations among the probes and correlations within the bath, and show that entanglement improves thermometry at short times whereas, if the interaction time is not constrained, coherence rather than entanglement, is the key resource in quantum thermometry.

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“…by preparing an initially entangled N-ancilla state [1,2]. Alternatively, one may perform N sequential measurements on the same ancilla [19][20][21][22], in such a way that the outcomes are correlated. Specifically in the context of thermometry, this method would generally not improve the accuracy of temperature estimation [21], but this could in principle change using adaptive schemes [22].…”

mentioning

confidence: 99%

Collisional Quantum Thermometry

et al. 2019

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We introduce a general framework for thermometry based on collisional models, where ancillas probe the temperature of the environment through an intermediary system. This allows for the generation of correlated ancillas even if they are initially independent. Using tools from parameter estimation theory, we show through a minimal qubit model that individual ancillas can already outperform the thermal Cramer-Rao bound. In addition, due to the steady-state nature of our model, when measured collectively the ancillas always exhibit superlinear scalings of the Fisher information. This means that even collective measurements on pairs of ancillas will already lead to an advantage. As we find in our qubit model, such a feature may be particularly valuable for weak system-ancilla interactions. Our approach sets forth the notion of metrology in a sequential interactions setting, and may inspire further advances in quantum thermometry.

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Estimating temperature via sequential measurements

Cited by 61 publications

References 33 publications

Thermometry in the quantum regime: recent theoretical progress

Thermometry in the quantum regime: recent theoretical progress

Two-qubit quantum probes for the temperature of an Ohmic environment

Collisional Quantum Thermometry

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