scholarly journals Quantum Fisher Information of Decohered W and GHZ Superposition States with Arbitrary Relative Phase

2017 ◽  
Author(s):  
Volkan Erol
Keyword(s):  
Quantum System ◽  
Recent Work ◽  
Fisher Information ◽  
Relative Phase ◽  
Quantum Fisher Information ◽  
Phase Sensitivity ◽  
Quantum Metrology ◽  
Noisy Channels ◽  
Noise Parameters ◽  
Superposition States

Quantum Fisher Information (QFI) is a very useful concept for analyzing situations that require phase sensitivity. It become a popular topic especially in Quantum Metrology domain. In this work, we study the changes in quantum Fisher information (QFI) values for one relative arbitrary phased quantum system consisting of a superposition of N Qubits W and GHZ states. In a recent work [7], QFI values of this mentioned system for N qubits were studied. In this work, we extend this problem for the changes of QFI values in some noisy channels for the studied system. We show the changes in QFI depending on noise parameters. We report interesting results for different type of decoherence channels. We show the general case results for this problem.

scholarly journals Quantum Fisher Information of W and GHZ State Superposition under Decoherence

2017 ◽  
Author(s):  
Volkan Erol
Keyword(s):  
Quantum System ◽  
Recent Work ◽  
Fisher Information ◽  
Quantum Fisher Information ◽  
Ghz State ◽  
Noisy Channels ◽  
Noise Parameters ◽  
Ghz States

We study the changes in quantum Fisher information (QFI) values for one quantum system consisting of a superposition of W and GHZ states. In a recent work [6], QFI values of this mentioned system studied. In this work, we extend this problem for the changes of QFI values in some noisy channels. We show the change in QFI depending on noise parameters. We report interesting results for different type of decoherence channels.

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 Quantum Fisher Information of Several Qubitsin the Superposition of A GHZ and two W Stateswith Arbitrary Relative Phase

2014 ◽  
Vol 53 (9) ◽  
pp. 3219-3225 ◽  
Author(s):  
Fatih Ozaydin ◽  
Azmi Ali Altintas ◽  
Sinan Bugu ◽  
Can Yesilyurt ◽  
Metin Arik
Keyword(s):  
Fisher Information ◽  
Relative Phase ◽  
Quantum Fisher Information

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.

Characterizations of symmetric monotone metrics on the state space of quantum systems

2006 ◽  
Vol 6 (7) ◽  
pp. 597-605
Author(s):  
F. Hansen
Keyword(s):  
State Space ◽  
Quantum System ◽  
Fisher Information ◽  
Quantum Fisher Information ◽  
Classical Case ◽  
Riemannian Metric ◽  
Quantum Systems ◽  
The State ◽  
Stochastic Mappings

The quantum Fisher information is a Riemannian metric, defined on the state space of a quantum system, which is symmetric and decreasing under stochastic mappings. Contrary to the classical case such a metric is not unique. We complete the characterization, initiated by Morozova, Chentsov and Petz, of these metrics by providing a closed and tractable formula for the set of Morozova-Chentsov functions. In addition, we provide a continuously increasing bridge between the smallest and largest symmetric monotone metrics.

Quantum Fisher information for superpositions of spin states

2010 ◽  
Vol 10 (5&6) ◽  
pp. 498-508
Author(s):  
H.-N. Xiong ◽  
J. Ma ◽  
W.-F. Liu ◽  
X. Wang
Keyword(s):  
Fisher Information ◽  
Shot Noise ◽  
Quantum Fisher Information ◽  
Entanglement Measure ◽  
Spin States ◽  
Phase Sensitivity ◽  
Noise Limit ◽  
Necessary And Sufficient ◽  
Shot Noise Limit ◽  
Dicke States

In terms of quantum Fisher information, a quantity $\chi^{2}$ was introduced by Pezz\'{e} and Smerzi, which is a multiparticle entanglement measure, and provides a necessary and sufficient condition for sub-shot-noise phase estimation sensitivity. We derive a general expression of $\chi ^{2}$ for arbitrary symmetric multiqubit states with nonzero mean spins. It is shown that the entangled symmetric states are useful for phase sensitivity beyond the shot-noise limit. Using the expression, we explicitly examine a series of superpositions of spin states. We find that the superpositions of Dicke states perform better than Dicke states themselves in phase esitmation. Although the spin coherent states themselves only have a shot-noise limit phase sensitivity, their superpositions may reach the Heisenberg limit.

Fisher and skew information for two-qubit Bell states under decoherence effects

2020 ◽  
Vol 18 (04) ◽  
pp. 2050018
Author(s):  
R. Laghmach ◽  
H. El Hadfi ◽  
B. Maroufi ◽  
M. Daoud
Keyword(s):  
Fisher Information ◽  
Dynamical Behavior ◽  
Quantum Fisher Information ◽  
Bell States ◽  
Thermal Entanglement ◽  
Noisy Channels ◽  
Phase Damping ◽  
Skew Information ◽  
Amplitude Damping Channel ◽  
Depolarizing Channel

We give the explicit expressions of quantum Fisher information and skew information for a two-qubit Bell states. We investigate their dynamics under the decoherence effects: phase-damping channel, depolarizing channel and amplitude-damping channel. We also discuss the thermal entanglement quantified by Wootters concurrence for these three decoherence channels and we compare its dynamical behavior with the quantum Fisher information and skew information. We then use this comparison to investigate the influence of noisy channels on thermal entanglement and its role in boosting the performance of metrology protocols. It is shown that the correlations in two-qubit Bell states are more resistant to phase-damping channel and depolarizing channels.

Optimal temperature estimation for a XXZ spin-1 2 chain coupled locally to independent thermal baths

2020 ◽  
Vol 34 (36) ◽  
pp. 2050425
Author(s):  
Chao-Quan Wang
Keyword(s):  
Quantum System ◽  
Fisher Information ◽  
Open Quantum System ◽  
Quantum Fisher Information ◽  
Steady States ◽  
Optimal Time ◽  
Quantum Master Equation ◽  
Optimal Temperature ◽  
Temperature Estimation ◽  
Open Quantum

Temperature as an environmental parameter influences the evolution of an open quantum system. In detail, temperature lies in Lindblad operator of quantum master equation that the evolution of an open quantum system follows. Hence, one can implement a temperature estimation of thermal baths through a measurement of quantum Fisher information about temperature brought from quantum states. Such a method by calculating quantum Fisher information about a parameter to estimate its value avoids measuring the parameter directly and it does not change the value of the parameter due to making measurements. In this paper, we consider a model consisting of a XXZ spin-[Formula: see text] chain coupled locally to independent thermal baths with different temperature. Based on the model, we investigate optimal temperature estimation for thermal baths with respect to an open quantum system subjected to non-steady states. We first study optimal probe time for temperature estimation in the case of non-steady states and find that the optimal time shows different features for different types of system variables. It proves that in a certain duration there exists a tradeoff between the trial times and the attaining amount of Fisher information in each trial. In addition, we pay attention to an issue on optimal probe states. We demonstrate that in many cases the optimal states are not always the maximally entangled states and even maybe the separable states, which is related with the measuring time, system couplings.

Sign in / Sign up

Export Citation Format

Share Document