Quantum enhanced estimation of diffusion

Branford, Dominic; Gagatsos, Christos N.; Grover, Jai; Hickey, Alexander J.; Datta, Animesh

doi:10.1103/physreva.100.022129

Cited by 9 publications

(10 citation statements)

References 75 publications

(119 reference statements)

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“…Under certain regularity assumptions, the QFI matrix encodes the ultimate precision bounds on the estimation of unknown parameters encoded in a density matrix (know as quantum Cramer-Rao bounds), while the SLDs and their commutators determine whether such bounds may be saturated with physically realizable measurements [5,6]. The associated applications are plenty, including phase and frequency estimation [4,[7][8][9][10][11][12][13][14][15][16][17], estimation of noise parameters [18][19][20][21][22][23], joint estimation of unitary and/or noisy parameters [24][25][26][27][28][29][30][31], sub-wavelength resolution of optical sources [32][33][34][35][36][37][38], nano-scale thermometry [39][40][41][42][43][44][45], and estimation of Hamiltonian parameters in the presence of phase-transitions [46][47][48]. The most common approach for ...…”

Section: Introductionmentioning

confidence: 99%

Non-orthogonal bases for quantum metrology

Genoni¹,

Tufarelli²

2019

J. Phys. A: Math. Theor.

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Many quantum statistical models are most conveniently formulated in terms of non-orthonormal bases. This is the case, for example, when mixtures and superpositions of coherent states are involved. In these instances, we show that the analytical evaluation of the quantum Fisher information may be greatly simplified by bypassing both the diagonalization of the density matrix and the orthogonalization of the basis. The key ingredient in our method is the Gramian matrix (i.e. the matrix of scalar products between basis elements), which may be interpreted as a metric tensor for index contraction. As an application, we derive novel analytical results for several estimation problems involving noisy Schrödinger cat states.

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Section: Introductionmentioning

confidence: 99%

Non-orthogonal bases for quantum metrology

Genoni¹,

Tufarelli²

2019

J. Phys. A: Math. Theor.

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“…Optically trapped particles may be able to detect dark matter [15] and exotic physics, especially when operated at [16,17] or beyond [7,8,9] the standard quantum limit. Attaining the requirements for achieving the primary science objectives of MAQRO (SO1-3) will enhance the detection sensitivity to sources of anomalous diffusion [18,19] to unprecedented degrees.…”

Section: Science Objectivesmentioning

confidence: 99%

Research campaign: Macroscopic quantum resonators (MAQRO)

Kaltenbaek

Arndt

Aspelmeyer

et al. 2023

Quantum Sci. Technol.

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The objective of the proposed MAQRO mission is to harness space for achieving long free-fall times, extreme vacuum, nano-gravity, and cryogenic temperatures to test the foundations of physics in macroscopic quantum experiments at the interface with gravity. Developing the necessary technologies, achieving the required sensitivities and providing the necessary isolation of macroscopic quantum systems from their environment will lay the path for developing novel quantum sensors. Earlier studies showed that the proposal is feasible but that several critical challenges remain, and key technologies need to be developed. Recent scientific and technological developments since the original proposal of MAQRO promise the potential for achieving additional science objectives. The proposed research campaign aims to advance the state of the art and to perform the first macroscopic quantum experiments in space. Experiments on the ground, in micro-gravity, and in space will drive the proposed research campaign during the current decade to enable the implementation of MAQRO within the subsequent decade.

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“…The value of Λ DP is extremely small, and it will be a challenge to achieve an even smaller Λ min . Options to achieve that can be to use high mass densities like, e.g., by using magnetically levitated superconducting spheres [22], by using optomechanical squeezing of the initial momentum uncertainty [26], or by using very long free evolution times as suggested in MAQRO [20,21].…”

Section: The Feasibility Of Testing For Gravitational Decoherencementioning

confidence: 99%

“…That means, if we succeed performing matter-wave interferometry with expansion times on the order of 100 s with high mass densities as envisaged by MAQRO, we should be able to conclusively test the DP model. If we can, in addition, make use of momentum squeezing as proposed by Branford et al [26], this may even become possible for shorter expansion times. This might be necessary if we cannot achieve the extremely high vacuum envisioned for MAQRO [21].…”

Section: The Feasibility Of Testing For Gravitational Decoherencementioning

confidence: 99%

Feasibility considerations for free-fall tests of gravitational decoherence

Kaltenbaek

2022

AVS Quantum Science

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Space offers exciting opportunities to test the foundations of quantum physics using macroscopic quantum superpositions. It has been proposed to perform such tests in a dedicated space mission (MAQRO) using matter-wave interferometry with massive test particles or monitoring how the wave function of a test particle expands over time. Such experiments could, test quantum physics with sufficiently high precision to resolve potential deviations from its unitary evolution due to gravitational decoherence. For example, such deviations have been predicted by the Diósi-Penrose (DP) model and the Károlyházy (K) model. The former predicts the collapse of massive or large superpositions due to a non-linear modification of quantum evolution. The latter predicts decoherence because of an underlying uncertainty of space time. Potential advantages of a space environment are (1) long free-fall times, (2) low noise, and (3) taking a high number of data points over several years in a dedicated space mission. In contrast to interferometric tests, monitoring wave function expansion is less complex, but it does face some practical limitations. Here, we will discuss limitations of such non-interferometric experiments due to the limited number of data points achievable during a mission lifetime. Our results show that it will require an interferometric approach to conclusively test for gravitational decoherence as predicted by the DP or K models. In honor of the novel prize of Sir Roger Penrose, we will focus our discussion on the Diósi-Penrose model.

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Quantum enhanced estimation of diffusion

Cited by 9 publications

References 75 publications

Non-orthogonal bases for quantum metrology

Non-orthogonal bases for quantum metrology

Research campaign: Macroscopic quantum resonators (MAQRO)

Feasibility considerations for free-fall tests of gravitational decoherence

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