Growing Quantum Simulations using Trapped Ions

While trapped ions have demonstrated the highest gate fidelities of any quantum platform, the number of accessible qubits remains limited. I will present near-term routes to addressing this challenge across the quantum stack, together with applications to quantum simulation.

 

At the circuit level, we employ an efficient qubit encoding to study the thermalization of a Z₂ lattice gauge theory [1]. Another encoding, based on the multiscale entanglement renormalization ansatz, allows us to encode size- N systems into O(log N) qubits; we use this capability to demonstrate the log(N) scaling of subsystem entanglement entropy near a critical point [2].

 

At the gate level, to counter the increase in control noise with circuit depth, we demonstrate hybrid analog-digital protocols that allow us to realize non-commuting three- and four-body interactions without Trotter error. We employ this protocol to realize a topological spin chain exhibiting prethermal strong zero modes persisting at high temperature [3].

 

At the hardware level, we use ¹⁷²Yb⁺ ions to sympathetically cool ¹⁷¹Yb⁺ qubit ions in mixed-species chains of up to 23 ions, allowing us to counter the dominant source of noise while preserving full gate connectivity.

 

Looking forward, I will present progress on realizing a fast, coherent, photonic interface [4] based on the integration of a micro-fabricated surface electrode ion trap for 137 Ba + ions with a coaxial optical resonator.