Quantum Physics Letters
Journal license

Journal

Quantum Physics Letters


Volume
& Issue

Volume 11, Issue 1


Published
on

April 1, 2022


Pages

9-12


DOI

Article

Two Simple Algorithms for Testing the Entanglement Status of an N-qubit Pure Quantum State

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Authors

Dhananjay P. Mehendale* Affiliation:
Department of Physics, Savitribai Phule University of Pune, Pune, India-411007


Abstract

An N-qubit pure quantum state is “separable” if and only if it can be factored into N 1-qubit factors. Otherwise, the state is an “entangled” state. In this paper we develop two simple algorithms, one “classical” and the other “quantum”, to determine the entanglement status of an N-qubit pure quantum state. First we develop a “classical” algorithm to determine entanglement status which is of the exponential order, $O(2^N)$. We then develop an efficient “quantum” algorithm for doing the same task and it is of the polynomial order, $O(N^2)$. This new “quantum” algorithm makes use of the “quantum” speedup available for finding the “inner product” of two vectors [5]. The new “quantum” algorithm also assumes the availability of sufficiently many copies of the N-qubit pure quantum state to be tested for determining its entanglement status.


Keywords

Entanglement and Separability, Partial Measurement, Inner Product


Citation

Mehendale, D. P. (2022). Two simple algorithms for testing the entanglement status of an n-qubit pure quantum state. Quantum Physics Letters, 11(1), 9–12. https://doi.org/10.18576/qpl/110102

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