Universal quantum simulation with pre-threshold superconducting qubits: Single-excitation subspace method

Understand

We propose a method for general-purpose quantum computation and simulation that is well suited for today's pre-threshold-fidelity superconducting qubits.

• This approach makes use of the $n$-dimensional single-excitation subspace (SES) of a system of $n$ tunably coupled qubits.
• It can be viewed as a nonscalable special case of the standard gate-based quantum computing model, but allows many operations in the unitary group SU($n$) to be implemented by a single application of the Hamiltonian.
• Our approach bypasses the need to decompose the evolution operator into elementary gates, making large, nontrivial computations possible without error correction.