# Operations with elements of transferred density matrix via unitary transformations at receiver side

## TL;DR

This paper introduces a method using unitary transformations at the receiver to manipulate transferred density matrix elements, enabling operations like zeroing, rearranging, and linear combination, demonstrated through numerical simulations on a spin chain.

## Contribution

It presents a novel protocol for performing matrix element operations via unitary transformations at the receiver side in quantum state transfer.

## Key findings

- Successfully zeroed out specific matrix elements
- Rearranged matrix elements as desired
- Simulated operations on a 42-node spin chain

## Abstract

Using the tool of unitary transformations of the extended receiver we perform simple operations with the non-diagonal elements of the initial sender's density matrix after their transferring to the receiver. These operations are following: turning some matrix elements to zero, rearranging the matrix elements and preparing their linear combinations with required coefficients. We also propose a protocol for solving a system of linear algebraic equations with a system of two equations as an example. Such operations are numerically simulated on the basis of 42-node spin-1/2 chain with the two-qubit sender and receiver.