English
Related papers

Related papers: Quantum fidelity for arbitrary Gaussian states

200 papers

We describe an optimized, self-correcting procedure for the Bayesian inference of pure quantum states. By analyzing the history of measurement outcomes at each step, the procedure returns the most likely pure state, as well as the optimal…

Quantum Physics · Physics 2015-09-14 Amir Kalev , Itay Hen

The fidelity of a quantum transformation is strongly linked with the prior partial information of the state to be transformed. We illustrate this interesting point by proposing and demonstrating the superior cloning of coherent states with…

Quantum Physics · Physics 2009-11-13 Metin Sabuncu , Gerd Leuchs , Ulrik L. Andersen

Quantum teleportation with an arbitrary two-qubit state can be appropriately characterized in terms of maximal fidelity and fidelity deviation. The former quantifies optimality of the process and is defined as the maximal average fidelity…

Quantum Physics · Physics 2020-03-23 Arkaprabha Ghosal , Debarshi Das , Saptarshi Roy , Somshubhro Bandyopadhyay

We calculate the quantum Cram\'er--Rao bound for the sensitivity with which one or several parameters, encoded in a general single-mode Gaussian state, can be estimated. This includes in particular the interesting case of mixed Gaussian…

Quantum Physics · Physics 2017-02-08 Olivier Pinel , Pu Jian , Claude Fabre , Nicolas Treps , Daniel Braun

We calculate the quantum Cram\'er--Rao bound for the sensitivity with which one or several parameters, encoded in a general single-mode Gaussian state, can be estimated. This includes in particular the interesting case of mixed Gaussian…

Quantum Physics · Physics 2015-06-16 O. Pinel , P. Jian , N. Treps , C. Fabre , and D. Braun

The interferometric power of a bipartite quantum state quantifies the precision, measured by quantum Fisher information, that such a state enables for the estimation of a parameter embedded in a unitary dynamics applied to one subsystem…

Quantum Physics · Physics 2014-08-25 Gerardo Adesso

We propose a measure of nonclassical correlation $N_{\mathcal F}^{\mathcal G}$ in terms of local Gaussian unitary operations based on square of the fidelity $\mathcal F$ for bipartite continuous-variable systems. This quantity is easier to…

Quantum Physics · Physics 2019-02-01 Liang Liu , Xiaofei Qi , Jinchuan Hou

Relativistic quantum metrology provides an optimal strategy for the estimation of parameters encoded in quantum fields in flat and curved spacetime. These parameters usually correspond to physical quantities of interest such as proper…

Quantum Physics · Physics 2017-05-25 Dominik Šafránek , Jan Kohlrus , David Edward Bruschi , Antony R. Lee , Ivette Fuentes

The fidelity susceptibility measures sensitivity of eigenstates to a change of an external parameter. It has been fruitfully used to pin down quantum phase transitions when applied to ground states (with extensions to thermal states). Here…

Disordered Systems and Neural Networks · Physics 2020-04-10 Piotr Sierant , Artur Maksymov , Marek Kuś , Jakub Zakrzewski

We demonstrate the capability of continuous variable Gaussian states to communicate multipartite quantum information. A quantum teamwork protocol is presented according to which an arbitrary possibly entangled multimode state can be…

Quantum Physics · Physics 2009-08-13 Jing Zhang , Gerardo Adesso , Changde Xie , Kunchi Peng

We consider the storage and transmission of a Gaussian distributed set of coherent states of continuous variable systems. We prove a limit on the average fidelity achievable when the states are transmitted or stored by a classical channel,…

Quantum Physics · Physics 2009-11-10 K. Hammerer , M. M. Wolf , E. S. Polzik , J. I. Cirac

We study a quantum teleportation scheme between two nanomechanical modes without local interaction. The nanomechanical modes are linearly coupled to and connected by the continuous variable modes of a superconducting circuit consisting of a…

Quantum Physics · Physics 2011-07-26 L. Tian , S. M. Carr

Various fidelity measures can be defined between two quantum processes especially when at least one of them is non-unitary. In this paper we consider two such measures of state averaged process fidelity, put forward an efficient procedure…

Mathematical Physics · Physics 2011-11-11 Joydip Ghosh

Recently it has been argued that all presently performed continuous variable quantum teleportation experiments could be explained using a local hidden variable theory. In this paper we study a modification of the original protocol which…

Quantum Physics · Physics 2007-08-04 Aurel Gabris , Girish S. Agarwal

We study quantum fidelity, the overlap between two ground states of a many-body system, focusing on the thermodynamic regime. We show how drop of fidelity near a critical point encodes universal information about a quantum phase transition.…

Quantum Physics · Physics 2015-05-20 Marek M. Rams , Bogdan Damski

Coherence and correlation are key features of the quantum system. Quantifying these quantities are astounding task in the framework of resource theory of quantum information processing. In this article, we identify an affinity-based metric…

Quantum Physics · Physics 2021-02-11 R. Muthuganesan , V. K. Chandrasekar , R. Sankaranarayanan

Gaussian quantum channels constitute a cornerstone of continuous-variable quantum information science, underpinning a wide array of protocols in quantum optics and quantum metrology. While the action of such channels on arbitrary states is…

Quantum Physics · Physics 2026-02-24 Pritam Chattopadhyay , Saikat Sur , Jonas F. G. Santos

We analyze mean fidelity between random density matrices of size N, generated with respect to various probability measures in the space of mixed quantum states: Hilbert-Schmidt measure, Bures (statistical) measure, the measures induced by…

Quantum Physics · Physics 2009-11-10 Karol Zyczkowski , Hans-Jurgen Sommers

A bipartite quantum state is tomographically faithful when it can be used as an input of a quantum operation acting on one of the two quantum systems, such that the joint output state carries a complete information about the operation…

Quantum Physics · Physics 2009-11-11 G. M. D'Ariano , M. F. Sacchi

The fidelity and local unitary transformation are two widely useful notions in quantum physics. We study two constrained optimization problems in terms of the maximal and minimal fidelity between two bipartite quantum states undergoing…

Quantum Physics · Physics 2015-11-23 Lin Zhang , Lin Chen , Kaifeng Bu