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Ancilla-assisted frequency estimation under phase covariant noises with Greenberger-Horne-Zeilinger states [article]

Rui-Jie Cai, Wei Zhong, Lan Zhou, Yu-Bo Sheng
2020 arXiv   pre-print
It has been demonstrated that the optimal sensitivity achievable with Greenberger-Horne-Zeilinger states is the same as that with uncorrelated probes in the frequency estimation in the presence of uncorrelated  ...  Here, we extend this issue by examining the optimal frequency sensitivities achievable by the use of ancilla-assisted strategy, which has been proposed recently for robust phase estimation.  ...  This is well-known Heisenberg limit 1/N and attainable by means of Greenberger-Horne-Zeilinger (GHZ) states [12, 13] . However, these exotic states are of extremely delicate and fragile.  ... 
arXiv:2006.11498v1 fatcat:fgmxhrlobngozh4gt2l4kauycu

A Geometric Perspective on Quantum Parameter Estimation [article]

Jasminder S. Sidhu, Pieter Kok
2019 arXiv   pre-print
estimation using Gaussian states.  ...  with classical technologies.  ...  Greenberger, M. A. Horne, and A. Zeilinger, in Bell’s Theorem, 100 A. Fujiwara, J. Phys. A: Math. Gen. 39, 12489 (2006).  ... 
arXiv:1907.06628v2 fatcat:qj2t5a4lrfh57iutl25ns2tfge

Experimental progress on quantum coherence: detection, quantification, and manipulation [article]

Kang-Da Wu, Alexander Streltsov, Bartosz Regula, Guo-Yong Xiang, Chuan-Feng Li, Guang-Can Guo
2021 arXiv   pre-print
We then consider experimental detection and quantification of coherence, experimental state conversion and coherence distillation, and experiments investigating the dynamics of quantum coherence.  ...  Therein, the authors generate highly entangled three-and four-qubit states -the Greenberger-Horne-Zeilinger state, W state, and cluster state -and use stabilizer measurements to ensure that measuring few  ...  In particular, after preparation in a generalized Bell diagonal state, the multiqubit ensemble is left to evolve under phase damping noise.  ... 
arXiv:2105.06854v1 fatcat:mmuzol24cndr5mufjs4ifalway

Frequency estimation under non-Markovian spatially correlated quantum noise: Restoring superclassical precision scaling [article]

Francisco Riberi, Leigh M. Norris, Felix Beaudoin, Lorenza Viola
2022 arXiv   pre-print
We study the estimation precision attainable by entanglement-enhanced Ramsey interferometry in the presence of spatiotemporally correlated non-classical noise.  ...  As a result, superclassical precision scaling is asymptotically restored for initial entangled states, including experimentally accessible one-axis spin-squeezed states.  ...  L.V. also acknowledges valuable exchange with John Gough on issues related to classicality of open quantum dynamics.  ... 
arXiv:2204.10798v1 fatcat:kqsohq2xpre4vc3nqbstazvi4y

Photonic Quantum Metrology [article]

Emanuele Polino, Mauro Valeri, Nicolò Spagnolo, Fabio Sciarrino
2020 arXiv   pre-print
Here we review the basic concepts behind quantum metrology and then focus on the application of photonic technology for this task, with particular attention to phase estimation.  ...  of noise.  ...  A class of N00N-like states, where photons are distributed along different modes (for example N photons along N spatial modes maximally entangled in the polarization degree of freedom), are called Greenberger-Horne-Zeilinger  ... 
arXiv:2003.05821v1 fatcat:rptsonccwnh7lkib5jybb2wkra

Photonic quantum metrology

Emanuele Polino, Mauro Valeri, Nicolò Spagnolo, Fabio Sciarrino
2020 AVS Quantum Science  
along N spatial modes maximally entangled in the polarization degree of freedom), are called Greenberger-Horne-Zeilinger (GHZ) states. 447 Such states were realized with up to 10 spatially separated  ...  Finally, ancilla-assisted schemes 232,704-708 are those where a part of the probe, generally entangled with the other part, does not interact with the system and is directly measured.  ... 
doi:10.1116/5.0007577 fatcat:6ueiotef5jgjva4nkgamwcjc5y

Quantum-enhanced measurements without entanglement

Daniel Braun, Gerardo Adesso, Fabio Benatti, Roberto Floreanini, Ugo Marzolino, Morgan W. Mitchell, Stefano Pirandola
2018 Reviews of Modern Physics  
parameters or parameters characterizing non-equilibrium states; and the use of quantum phase transitions.  ...  In the following we review alternative mechanisms, notably the use of more general quantum correlations such as quantum discord, identical particles, or non-trivial hamiltonians; the estimation of thermodynamical  ...  For instance, thinking of each probe as a qubit for simplicity, and fixing the generator H to be the Pauli matrix σ z , one can either consider a parallel scheme with N input probes in the Greenberger-Horne-Zeilinger  ... 
doi:10.1103/revmodphys.90.035006 fatcat:bjyimoxvffa5jgvq73yo7t2rjm

Quantum metrology with nonclassical states of atomic ensembles

Luca Pezzè, Augusto Smerzi, Markus K. Oberthaler, Roman Schmied, Philipp Treutlein
2018 Reviews of Modern Physics  
All these factors call for generating non-classical atomic states designed for phase estimation in atomic clocks and atom interferometers, exploiting many-body entanglement to increase the sensitivity  ...  The goal of this article is to review and illustrate the theory and the experiments with atomic ensembles that have demonstrated many-particle entanglement and quantum-enhanced metrology.  ...  Acknowledgments 59 ACKNOWLEDGMENTS We are indebted to our colleagues and collaborators with whom we have shared many useful discussions over the past years. In particular, we would like to thank B.  ... 
doi:10.1103/revmodphys.90.035005 fatcat:k3fepsgx6ndd7cmvw2zj7i46ii

Quantum information with Gaussian states

X WANG, T HIROSHIMA, A TOMITA, M HAYASHI
2007 Physics reports  
and strong Gaussian states and the quantum channel capacity, mathematical theory of quantum entanglement and state estimation for Gaussian states.  ...  Extending the existing results of quantum information with discrete quantum states to the case of continuous variable quantum states is an interesting theoretical job.  ...  Then, there exists a vector Φ such that Φ ∈ N ∩ N ( This is a subspace of the phase space X B and is defined as the phase space of the subsystem C (dim X C = 2f C ).  ... 
doi:10.1016/j.physrep.2007.04.005 fatcat:qouvjxyqlfewfgxj435qpa3a2a

Thermometry in the quantum regime: Recent theoretical progress [article]

Mohammad Mehboudi, Anna Sanpera, Luis A. Correa
2019 arXiv   pre-print
In this review, we report the most recent theoretical developments dealing with accurate estimation of very low temperatures in quantum systems.  ...  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  ...  As it turns out, preparing the probe in a maximally entangled Greenberger-Horne-Zeilinger (GHZ) state [209] and choosing Ω > 0 leads to a maximum transient quantum Fisher information larger than its  ... 
arXiv:1811.03988v2 fatcat:p5rkxgbrdvhplcq3dblnpeu72u

Phase Transitions in Light-Matter Systems for Quantum Sensing [article]

Louis Garbe
2021 arXiv   pre-print
We show that even this finite-size system displays a phase transition, which can be used to measure the frequency of the qubit and the field with improved accuracy.  ...  This mechanism creates a rich phase diagram containing both phase transitions and instabilities. A second topic is the use of these transitions for sensing applications.  ...  limit can be achieved by using Greenberger-Horne-Zeilinger (GHZ) states |ψ 0 ⟩ = |↓↓..↓⟩+|↑↑..↑⟩ √ .  ... 
arXiv:2011.01995v2 fatcat:uigxgjp6avdqxidef77f5fx2se

Noisy intermediate-scale quantum (NISQ) algorithms [article]

Kishor Bharti, Alba Cervera-Lierta, Thi Ha Kyaw, Tobias Haug, Sumner Alperin-Lea, Abhinav Anand, Matthias Degroote, Hermanni Heimonen, Jakob S. Kottmann, Tim Menke, Wai-Keong Mok, Sukin Sim (+2 others)
2021 arXiv   pre-print
A universal fault-tolerant quantum computer that can solve efficiently problems such as integer factorization and unstructured database search requires millions of qubits with low error rates and long  ...  In the search for quantum advantage with these devices, algorithms have been proposed for applications in various disciplines spanning physics, machine learning, quantum chemistry and combinatorial optimization  ...  The Greenberger-Horne-Zeilinger (GHZ) state, which is an essential resource in several quantum metrology proposals (Dür et al., 2014; Tóth and Apellaniz, 2014) , is an example of a non-trivial quantum  ... 
arXiv:2101.08448v2 fatcat:eawbcaxikjeb7d3wqbjhutjdxy

Quantum discord and its allies: a review of recent progress

Anindita Bera, Tamoghna Das, Debasis Sadhukhan, Sudipto Singha Roy, Aditi Sen(De), Ujjwal Sen
2017 Reports on progress in physics (Print)  
We review concepts and methods associated with quantum discord and related topics.  ...  We also describe their possible connections with other aspects of quantum information and beyond, including quantum communication, quantum computation, many-body physics, and open quantum dynamics.  ...  state GHZ Greenberger-Horne-Zeilinger state GQD Geometric quantum discord gW Generalized W state JC Jaynes-Cummings model LB Locally broadcastable LN Logarithmic negativity LU Local  ... 
doi:10.1088/1361-6633/aa872f pmid:28824014 fatcat:5yc5ehrgxzbzvp3cphtujad7xu

Modern applications of machine learning in quantum sciences [article]

Anna Dawid, Julian Arnold, Borja Requena, Alexander Gresch, Marcin Płodzień, Kaelan Donatella, Kim Nicoli, Paolo Stornati, Rouven Koch, Miriam Büttner, Robert Okuła, Gorka Muñoz-Gil (+17 others)
2022 arXiv   pre-print
We cover the use of deep learning and kernel methods in supervised, unsupervised, and reinforcement learning algorithms for phase classification, representation of many-body quantum states, quantum feedback  ...  This framework allows for the simulation of circuits that build Greenberger-Horne-Zeilinger and linear graph states of up to 60 qubits.  ...  Moreover, we discuss how ML methods assist researchers in tasks related to density estimation, as well as optimizations and speed-up of scientific experiments.  ... 
arXiv:2204.04198v1 fatcat:rae77aetd5hahnovchru6kjbcy

Quantum entanglement

Ryszard Horodecki, Paweł Horodecki, Michał Horodecki, Karol Horodecki
2009 Reviews of Modern Physics  
All our former experience with application of quantum theory seems to say: what is predicted by quantum formalism must occur in laboratory.  ...  An example of state admitting Schmidt decomposition in the d m case is the generalized Greenberger-Horne-Zeilinger state ͉⌿ A 1 ,. . .,A m ͘ = ͚ i=1 min͓d A 1 ,. . .  ...  change under adding local ancilla͒.  ... 
doi:10.1103/revmodphys.81.865 fatcat:6ahjbb4iyzfn5jgsocbeodmsqm
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