# A Quantum Model for Coherent Ising Machines: Discrete-time Measurement Feedback Formulation

## TL;DR

This paper introduces a quantum theoretical model for coherent Ising machines using discrete-time measurement feedback, providing insights into quantum coherence during optimization.

## Contribution

It presents a novel discrete-time measurement feedback model for CIMs and performs numerical simulations on a simple two-oscillator network.

## Key findings

- Quantum coherence persists during the optimization process.
- The model effectively captures the dynamics of CIMs with feedback.
- Numerical results demonstrate the feasibility of the approach.

## Abstract

Recently, the coherent Ising machine (CIM) as a degenerate optical parametric oscillator (DOPO) network has been researched to solve Ising combinatorial optimization problems. We formulate a theoretical model for the CIM with discrete-time measurement feedback processes, and perform numerical simulations for the simplest network, composed of two degenerate optical parametric oscillator pulses with the anti-ferromagnetic mutual coupling. We evaluate the extent to which quantum coherence exists during the optimization process.