Correlation between classical Fisher information and quantum squeezing properties of Gaussian pure states

Author(s):  
J.Q. Zhao
2018 ◽  
Vol 32 (05) ◽  
pp. 1850050 ◽  
Author(s):  
N. Metwally

In this paper, Fisher information for an accelerated system initially prepared in the X-state is discussed. An analytical solution, which consists of three parts: classical, the average over all pure states and a mixture of pure states, is derived for the general state and for Werner state. It is shown that the Unruh acceleration has a depleting effect on the Fisher information. This depletion depends on the degree of entanglement of the initial state settings. For the X-state, for some intervals of Unruh acceleration, the Fisher information remains constant, irrespective to the Unruh acceleration. In general, the possibility of estimating the state’s parameters decreases as the acceleration increases. However, the precision of estimation can be maximized for certain values of the Unruh acceleration. We also investigate the contribution of the different parts of the Fisher information on the dynamics of the total Fisher information.


2010 ◽  
Vol 49 (10) ◽  
pp. 2463-2475 ◽  
Author(s):  
Wan-Fang Liu ◽  
Li-Hua Zhang ◽  
Chun-Jie Li

2012 ◽  
Vol 571 ◽  
pp. 283-286
Author(s):  
Jia Qiang Zhao ◽  
Lian Zhen Cao ◽  
Huai Xin Lu

In this paper the Fisher information of Gaussian pure States is studied. Based on the definition of joint non-classical properties, we calculate the non-classical properties of Gaussian pure States. The results show that the Fisher information and Fisher length are efficacious tools to study the non-classical properties of quantum States.


2020 ◽  
Vol 18 (01) ◽  
pp. 1941022
Author(s):  
Matteo G. A. Paris

We address nearly pure quantum statistical models, i.e. situations where the information about a parameter is encoded in pure states weakly perturbed by the mixing with a parameter independent state, mimicking a weak source of noise. We show that the symmetric logarithmic derivative is left unchanged, and find an approximate analytic expression for the quantum Fisher information (QFI) which provides bounds on how much a weak source of noise may degrade the QFI.


Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 408
Author(s):  
Matteo Villani ◽  
Guillermo Albareda ◽  
Carlos Destefani ◽  
Xavier Cartoixà ◽  
Xavier Oriols

Without access to the full quantum state, modeling quantum transport in mesoscopic systems requires dealing with a limited number of degrees of freedom. In this work, we analyze the possibility of modeling the perturbation induced by non-simulated degrees of freedom on the simulated ones as a transition between single-particle pure states. First, we show that Bohmian conditional wave functions (BCWFs) allow for a rigorous discussion of the dynamics of electrons inside open quantum systems in terms of single-particle time-dependent pure states, either under Markovian or non-Markovian conditions. Second, we discuss the practical application of the method for modeling light–matter interaction phenomena in a resonant tunneling device, where a single photon interacts with a single electron. Third, we emphasize the importance of interpreting such a scattering mechanism as a transition between initial and final single-particle BCWF with well-defined central energies (rather than with well-defined central momenta).


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