# Inter-qubit interaction mediated by collective modes in a linear array of three-dimensional cavities

## TL;DR

This paper presents a modular design for linear arrays of 3D cavities with qubits, introducing a simulation-based method to estimate inter-qubit coupling strengths that aligns well with direct electromagnetic simulations.

## Contribution

It proposes a novel technique combining Hamiltonian models with HFSS simulations to estimate inter-qubit coupling in complex cavity arrays.

## Key findings

- Good agreement between estimated and simulated coupling strengths.
- Method is suitable for complex arrays where direct simulations are limited.
- Design facilitates flexible assembly of cavity-qubit systems.

## Abstract

A design of LEGO-like construction set that allows assembling of different linear arrays of three-dimensional (3D) cavities and qubits for circuit quantum electrodynamics (cQED) experiments has been developed. A study of electromagnetic properties of qubit-3D cavity arrays has been done by using high frequency structure simulator (HFSS). A technique for estimation of inter-qubit coupling strength between qubits embedded in different cavities of cavity array, which combines Hamiltonian description of the system with simple HFSS simulations, has been proposed. A good agreement between inter-qubit coupling strengths, which were obtained by using this technique and directly from simulation, demonstrates the suitability of the method for more complex qubit-cavity arrays where usage of finite-element electromagnetic simulators is limited.