Efficient qubit phase estimation using adaptive measurements
Por:
Rodriguez-Garcia, Marco A., Perez Castillo, Isaac, Barberis-Blostein, P.
Publicada:
4 jun 2021
Resumen:
Estimating correctly the quantum phase of a physical system is a central
problem in quantum parameter estimation theory due to its wide range of
applications from quantum metrology to cryptography. Ideally, the
optimal quantum estimator is given by the so-called quantum Cramer-Rao
bound, so any measurement strategy aims to obtain estimations as close
as possible to it. However, more often than not, the current
state-of-the-art methods to estimate quantum phases fail to reach this
bound as they rely on maximum likelihood estimators of non-identifiable
likelihood functions. In this work we thoroughly review various schemes
for estimating the phase of a qubit, identifying the underlying problem
which prohibits these methods to reach the quantum Cramer-Rao bound, and
propose a new adaptive scheme based on covariant measurements to
circumvent this problem. Our findings are carefully checked by Monte
Carlo simulations, showing that the method we propose is both
mathematically and experimentally more realistic and more efficient than
the methods currently available.
Filiaciones:
Rodriguez-Garcia, Marco A.:
Univ Nacl Autonoma Mexico, Inst Invest Matemat Aplicadas & Sistemas, Ciudad De Mexico 04510, Mexico
Perez Castillo, Isaac:
Univ Autonoma Metropolitana Iztapalapa, Dept Fis, San Rafael Atlixco 186, Ciudad De Mexico 09340, Mexico
Barberis-Blostein, P.:
Univ Nacl Autonoma Mexico, Inst Invest Matemat Aplicadas & Sistemas, Ciudad De Mexico 04510, Mexico
Gold
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