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Quantum State Estimation Using Weak Measurements


Affiliations
1 Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Manauli 140 306, India
 

We explore the possibility of using 'weak measurements' without 'weak value' for quantum state estimation. Since for weak measurements the disturbance caused during each measurement is small, we can rescue and recycle the state, unlike for the case of projective measurements. We use this property of weak measurements and design schemes for quantum state estimation for qubits and for Gaussian states. We show, via numerical simulations, that under certain circumstances, our method can outperform the estimation by projective measurements. It turns out that ensemble size plays an important role and the scheme based on recycling works better for small ensembles.

Keywords

Fidelity, Gaussian State, Projective Measurement, Qubit, State Estimation, Weak Measurement.
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  • Quantum State Estimation Using Weak Measurements

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Authors

Debmalya Das
Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Manauli 140 306, India
Arvind
Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Manauli 140 306, India

Abstract


We explore the possibility of using 'weak measurements' without 'weak value' for quantum state estimation. Since for weak measurements the disturbance caused during each measurement is small, we can rescue and recycle the state, unlike for the case of projective measurements. We use this property of weak measurements and design schemes for quantum state estimation for qubits and for Gaussian states. We show, via numerical simulations, that under certain circumstances, our method can outperform the estimation by projective measurements. It turns out that ensemble size plays an important role and the scheme based on recycling works better for small ensembles.

Keywords


Fidelity, Gaussian State, Projective Measurement, Qubit, State Estimation, Weak Measurement.

References





DOI: https://doi.org/10.18520/cs%2Fv109%2Fi11%2F1939-1945