Quantum fidelity measures for mixed states

YC Liang, YH Yeh, PEMF Mendonça… - Reports on Progress …, 2019 - iopscience.iop.org
Applications of quantum technology often require fidelities to quantify performance. These
provide a fundamental yardstick for the comparison of two quantum states. While this is …

[HTML][HTML] Variational quantum fidelity estimation

M Cerezo, A Poremba, L Cincio, PJ Coles - Quantum, 2020 - quantum-journal.org
Computing quantum state fidelity will be important to verify and characterize states prepared
on a quantum computer. In this work, we propose novel lower and upper bounds for the …

[HTML][HTML] Quantum coherence sets the quantum speed limit for mixed states

D Mondal, C Datta, S Sazim - Physics Letters A, 2016 - Elsevier
We cast observable measure of quantum coherence as a resource to control the quantum
speed limit (QSL) for unitary evolutions. For non-unitary evolutions, QSL depends on that of …

Statistical mixtures of states can be more quantum than their superpositions: Comparison of nonclassicality measures for single-qubit states

A Miranowicz, K Bartkiewicz, A Pathak, J Peřina Jr… - Physical Review A, 2015 - APS
A bosonic state is commonly considered nonclassical (or quantum) if its Glauber-Sudarshan
P function is not a classical probability density, which implies that only coherent states and …

Variational approach to the quantum separability problem

M Consiglio, TJG Apollaro, M Wieśniak - Physical Review A, 2022 - APS
We present the variational separability verifier (VSV), which is a variational quantum
algorithm that determines the closest separable state (CSS) of an arbitrary quantum state …

Optimal measurements for quantum fidelity between Gaussian states and its relevance to quantum metrology

C Oh, C Lee, L Banchi, SY Lee, C Rockstuhl, H Jeong - Physical Review A, 2019 - APS
Quantum fidelity is a measure to quantify the closeness between two quantum states. In an
operational sense, it is defined as the minimal overlap between the probability distributions …

Bell nonlocality and fully entangled fraction measured in an entanglement-swap** device without quantum state tomography

K Bartkiewicz, K Lemr, A Černoch, A Miranowicz - Physical Review A, 2017 - APS
We propose and experimentally implement an efficient procedure based on entanglement
swap** to determine the Bell nonlocality measure of Horodecki et al.[Phys. Lett. A 200 …

Experimental measurement of the Hilbert-Schmidt distance between two-qubit states as a means for reducing the complexity of machine learning

V Trávníček, K Bartkiewicz, A Černoch, K Lemr - Physical review letters, 2019 - APS
We report on the experimental measurement of the Hilbert-Schmidt distance between two
two-qubit states by many-particle interference. We demonstrate that our three-step method …

Method for universal detection of two-photon polarization entanglement

K Bartkiewicz, P Horodecki, K Lemr, A Miranowicz… - Physical Review A, 2015 - APS
Detecting and quantifying quantum entanglement of a given unknown state poses problems
that are fundamentally important for quantum information processing. Surprisingly, no direct …

Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix

K Bartkiewicz, J Beran, K Lemr, M Norek, A Miranowicz - Physical Review A, 2015 - APS
We describe a direct method to determine the negativity of an arbitrary two-qubit state in
experiments. The method is derived by analyzing the relation between the purity, negativity …