scholarly journals Symmetric Logarithmic Derivative of Fermionic Gaussian States

2018 ◽  
Author(s):  
Angelo Carollo ◽  
Bernardo Spagnolo ◽  
Davide Valenti
Keyword(s):  
Fisher Information ◽  
Logarithmic Derivative ◽  
Quantum Fisher Information ◽  
Closed Form Expression ◽  
Quantum Metrology ◽  
Many Body ◽  
Form Expression ◽  
Gaussian States ◽  
Many Body Systems ◽  
Thermal States

In this article we derive a closed form expression for the symmetric logarithmic derivative of Fermionic Gaussian states. This provides a direct way of computing the quantum Fisher Information for Fermionic Gaussian states. Applications range from quantum Metrology with thermal states to non-equilibrium steady states with Fermionic many-body systems.

scholarly journals Incompatibility in Multi-Parameter Quantum Metrology with Fermionic Gaussian States

Proceedings ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Angelo Carollo ◽  
Bernardo Spagnolo ◽  
Davide Valenti
Keyword(s):  
Fisher Information ◽  
Quantum Fisher Information ◽  
Spin Systems ◽  
Closed Form Expression ◽  
Quantum Metrology ◽  
Form Expression ◽  
Gaussian States ◽  
Optimal Measurement ◽  
Measurement Strategies ◽  
Thermal States

In this article we derive a closed form expression for the incompatibility condition in multi-parameter quantum metrology when the reference states are Fermionic Gaussian states. Together with the quantum Fisher information, the knowledge of the compatibility condition provides a way of designing optimal measurement strategies for multi-parameter quantum estimation. Applications range from quantum metrology with thermal states to non-equilibrium steady states with Fermionic and spin systems.

Quantum Fisher information width in quantum metrology

2018 ◽  
Vol 62 (4) ◽  
Author(s):  
Bo Liu ◽  
GuoLong Li ◽  
YanMing Che ◽  
Jie Chen ◽  
XiaoGuang Wang
Keyword(s):  
Fisher Information ◽  
Quantum Fisher Information ◽  
Quantum Metrology

scholarly journals Thermalization of Finite Many-Body Systems by a Collision Model

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1182 ◽  
Author(s):  
Onat Arısoy ◽  
Steve Campbell ◽  
Özgür E. Müstecaplıoğlu
Keyword(s):  
Weak Coupling ◽  
Target System ◽  
Model Description ◽  
Body System ◽  
Weak Coupling Regime ◽  
Many Body ◽  
Collision Model ◽  
System Transition ◽  
Many Body Systems ◽  
Thermal States

We construct a collision model description of the thermalization of a finite many-body system by using careful derivation of the corresponding Lindblad-type master equation in the weak coupling regime. Using the example of a two-level target system, we show that collision model thermalization is crucially dependent on the various relevant system and bath timescales and on ensuring that the environment is composed of ancillae which are resonant with the system transition frequencies. Using this, we extend our analysis to show that our collision model can lead to thermalization for certain classes of many-body systems. We establish that for classically correlated systems our approach is effective, while we also highlight its shortcomings, in particular with regards to reaching entangled thermal states.

scholarly journals Thermal states of random quantum many-body systems

2014 ◽  
Vol 90 (5) ◽  
Author(s):  
Yoshifumi Nakata ◽  
Tobias J. Osborne
Keyword(s):  
Many Body ◽  
Many Body Systems ◽  
Thermal States

Fisher information and uncertainty-like relationships in many-body systems

1999 ◽  
Vol 121-122 ◽  
pp. 729
Author(s):  
E. Romera ◽  
J.C. Angulo ◽  
J.S. Dehesa
Keyword(s):  
Fisher Information ◽  
Many Body ◽  
Many Body Systems

scholarly journals Remote State Design for Efficient Quantum Metrology with Separable and Non-Teleporting States

2021 ◽  
Vol 3 (1) ◽  
pp. 228-241
Author(s):  
Rahul Raj ◽  
Shreya Banerjee ◽  
Prasanta K. Panigrahi
Keyword(s):  
Parameter Estimation ◽  
Quantum Information ◽  
Fisher Information ◽  
Quantum Information Processing ◽  
Quantum Fisher Information ◽  
Quantum Correlations ◽  
Quantum States ◽  
Quantum Metrology ◽  
High Quantum ◽  
Non Local

Measurements leading to the collapse of states and the non-local quantum correlations are the key to all applications of quantum mechanics as well as in the studies of quantum foundation. The former is crucial for quantum parameter estimation, which is greatly affected by the physical environment and the measurement scheme itself. Its quantification is necessary to find efficient measurement schemes and circumvent the non-desirable environmental effects. This has led to the intense investigation of quantum metrology, extending the Cramér–Rao bound to the quantum domain through quantum Fisher information. Among all quantum states, the separable ones have the least quantumness; being devoid of the fragile non-local correlations, the component states remain unaffected in local operations performed by any of the parties. Therefore, using these states for the remote design of quantum states with high quantum Fisher information can have diverse applications in quantum information processing; accurate parameter estimation being a prominent example, as the quantum information extraction solely depends on it. Here, we demonstrate that these separable states with the least quantumness can be made extremely useful in parameter estimation tasks, and further show even in the case of the shared channel inflicted with the amplitude damping noise and phase flip noise, there is a gain in Quantum Fisher information (QFI). We subsequently pointed out that the symmetric W states, incapable of perfectly teleporting an unknown quantum state, are highly effective for remotely designing quantum states with high quantum Fisher information.

scholarly journals Quantum Fisher Information: Theory and Applications

2017 ◽  
Author(s):  
Volkan Erol
Keyword(s):  
Information Theory ◽  
Quantum Information ◽  
Fisher Information ◽  
Quantum Fisher Information ◽  
Research Area ◽  
Quantum Metrology ◽  
Information Research ◽  
Active Research ◽  
Information Domain ◽  
Active Research Area

Entanglement is at the heart of quantum technologies such as quantum information and quantum metrology. Providing larger quantum Fisher information (QFI), entangled systems can be better resources than separable systems in quantum metrology. QFI topic is a very active research area and it has many possible usage areas in quantum information domain. In this study, we review quantum Fisher information research with both from theoritical and application perspective.

scholarly journals Taming singularities of the quantum Fisher information

2021 ◽  
Author(s):  
Aaron Z. Goldberg ◽  
José L. Romero ◽  
Ángel S. Sanz ◽  
Luis L. Sánchez-Soto
Keyword(s):  
Density Matrix ◽  
Fisher Information ◽  
Statistical Models ◽  
Probability Distributions ◽  
Quantum Fisher Information ◽  
Quantum Metrology ◽  
Quantum Statistical ◽  
Information Matrices ◽  
Parameter Dependent ◽  
Ultimate Limit

Quantum Fisher information matrices (QFIMs) are fundamental to estimation theory: they encode the ultimate limit for the sensitivity with which a set of parameters can be estimated using a given probe. Since the limit invokes the inverse of a QFIM, an immediate question is what to do with singular QFIMs. Moreover, the QFIM may be discontinuous, forcing one away from the paradigm of regular statistical models. These questions of nonregular quantum statistical models are present in both single- and multiparameter estimation. Geometrically, singular QFIMs occur when the curvature of the metric vanishes in one or more directions in the space of probability distributions, while QFIMs have discontinuities when the density matrix has parameter-dependent rank. We present a nuanced discussion of how to deal with each of these scenarios, stressing the physical implications of singular QFIMs and the ensuing ramifications for quantum metrology.

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