Optimal two-qubit tomography based on local and global measurements: Maximal robustness against errors as described by condition numbers

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F14%3A33151852" target="_blank" >RIV/61989592:15310/14:33151852 - isvavai.cz</a>

Výsledek na webu

<a href="http://journals.aps.org/pra/pdf/10.1103/PhysRevA.90.062123" target="_blank" >http://journals.aps.org/pra/pdf/10.1103/PhysRevA.90.062123</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevA.90.062123" target="_blank" >10.1103/PhysRevA.90.062123</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Optimal two-qubit tomography based on local and global measurements: Maximal robustness against errors as described by condition numbers

Popis výsledku v původním jazyce

We present an error analysis of various tomographic protocols based on the linear inversion for the reconstruction of an unknown two-qubit state. We solve the problem of finding a tomographic protocol which is the most robust against errors in terms of the lowest value (i.e., equal to 1) of a condition number, as required by the Gastinel-Kahan theorem. In contrast, standard tomographic protocols, including those based on mutually unbiased bases, are nonoptimal for determining all the 16 elements of an unknown two-qubit density matrix. Our method is based on the measurements of the 16 generalized Pauli operators, where twelve of them can be locally measured, and the other four require nonlocal Bell measurements. Our method corresponds to selectively measuring, one by one, all the real and imaginary elements of an unknown two-qubit density matrix. We describe two experimentally feasible setups of this protocol for the optimal reconstruction of two photons in an unknown polarization state

Název v anglickém jazyce

Optimal two-qubit tomography based on local and global measurements: Maximal robustness against errors as described by condition numbers

Popis výsledku anglicky

We present an error analysis of various tomographic protocols based on the linear inversion for the reconstruction of an unknown two-qubit state. We solve the problem of finding a tomographic protocol which is the most robust against errors in terms of the lowest value (i.e., equal to 1) of a condition number, as required by the Gastinel-Kahan theorem. In contrast, standard tomographic protocols, including those based on mutually unbiased bases, are nonoptimal for determining all the 16 elements of an unknown two-qubit density matrix. Our method is based on the measurements of the 16 generalized Pauli operators, where twelve of them can be locally measured, and the other four require nonlocal Bell measurements. Our method corresponds to selectively measuring, one by one, all the real and imaginary elements of an unknown two-qubit density matrix. We describe two experimentally feasible setups of this protocol for the optimal reconstruction of two photons in an unknown polarization state

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BH - Optika, masery a lasery

OECD FORD obor

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Projekt

<a href="/cs/project/LO1305" target="_blank" >LO1305: Rozvoj centra pokročilých technologií a materiálů</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2014

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Review A

ISSN

1050-2947

e-ISSN

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Svazek periodika

90

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

12

Strana od-do

"062123-1"-"062123-12"

Kód UT WoS článku

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EID výsledku v databázi Scopus

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