Measuring entanglement of a rank-2 mixed state prepared on a quantum computer
Department for Theoretical Physics, Ivan Franko National University of Lviv, 12 Drahomanov St., 79005, Lviv, UA, Ukraine
Accepted: 9 May 2021
Published online: 20 May 2021
We study the entanglement between a certain qubit and the remaining system in rank-2 mixed states prepared on the quantum computer. The protocol, which we propose for this purpose, is based on the relation of geometric measure of entanglement with correlations between qubits. As a special case, we consider a two-qubit rank-2 mixed state and find the relation of concurrence with the geometric measure of entanglement. On the ibmq-melbourne quantum computer, we measure the geometric measure of entanglement in the cases of 2- and 4-qubit mixed quantum states which consist of Schrödinger cat states. We study the dependence of the value of entanglement on the parameter which defines the weight of pure states. Finally, we determine the concurrence of 2-qubit mixed state.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021