Quantum Information Science with Vibrational Degrees of Freedom of Trapped Ions

Kihwan Kim

Department of Physics, Tsinghua University

In this talk, I will describe our major efforts to achieve quantum advantage using trapped ions. Within the Noisy Intermediate-Scale Quantum (NISQ) realm, an important milestone is showing quantum advantage - outperforming classical computers on specific problems. So far, boson sampling with photons and random circuit sampling with superconducting qubits have achieved this. Here, I present two paths we are exploring to reach similar quantum advantages with trapped ions.

First, we construct scalable phononic networks using the vibrational modes of trapped ions. We have realized a small-scale phonon sampler and shown this is an ideal testbed, since single phonons can be prepared and measured deterministically without loss - addressing key limitations of photonic systems [1].

Second, we have developed a trap capable of holding a 2D crystal of ions, demonstrating its equivalence to the standard linear ion chain for quantum simulation. Specifically, we achieved adiabatic ground state preparation for transverse Ising models with up to 10 ions [2]. We plan to scale up the number of ions to achieve quantum advantage. We will discuss the difficulties and our strategy for overcoming challenges towards this goal.

[1] Wentao Chen, et al., Nature Physics 19, 877 (2023).

[2] Mu Qiao, et al., Nature Physics, online (2024).