# Non-adiabatic transformation of a spin-chain geometry via local control

## TL;DR

This paper demonstrates how to improve the fidelity of transforming a closed spin chain into an open one, or vice versa, by optimizing the control function of the spin-spin coupling in a non-adiabatic regime.

## Contribution

It introduces a method to enhance non-adiabatic state transformation fidelity in spin chains through tailored local control of exchange interactions.

## Key findings

- Optimized control functions increase transformation fidelity.
- Heuristic constraints limit feasible control functions.
- Applicable to antiferromagnetic quantum Ising chains.

## Abstract

We consider transformation from a closed to an open spin chain and vice versa produced by changing single link strength in a pair of neighboring spins. We show that in the non-adiabatic time domain fidelity of such a process can be increased by proper choosing of the control function for spin-spin exchange coupling. We obtain this function for an antiferromagnetic quantum Ising chain and present heuristic reasons restricting possible time-dependences of Hamiltonians applied for a high-fidelity control.