Dark spin-cats as biased qubits

Abstract

We present a biased atomic qubit, universally implementable across all atomic platforms, encoded as a `spin-cat' within ground state Zeeman levels. The key characteristic of our configuration is the coupling of the ground state spin manifold of size $F_g\gg 1$ to an excited Zeeman spin manifold of size $F_e=F_g-1$ using light. This coupling results in eigenstates of the driven atom that include exactly two dark states in the ground state manifold, which are decoupled from light and immune to spontaneous emission from the excited states. These dark states constitute the `spin-cat', leading to the designation `dark spin-cat'. We demonstrate that under strong Rabi drive and for large $F_g$, the `dark spin-cat' is autonomously stabilized against common noise sources and encodes a qubit with significantly biased noise. Specifically, the bit-flip error rate decreases exponentially with $F_g$ relative to the dephasing rate. We provide an analysis of dark spin-cats, their robustness to noise, and discuss bias-preserving single qubit and entangling gates, exemplified on a Rydberg tweezer platform.

References in corpus (13)

• Surface codes: Towards practical large-scale quantum computation
• Logical quantum processor based on reconfigurable atom arrays
• Robust randomized benchmarking of quantum processes
• Fault-tolerant quantum computation against biased noise
• Multi-qubit gates and Schrödinger cat states in an optical clock
• A dual-species Rydberg array
• Universal quantum operations and ancilla-based readout for tweezer clocks
• Benchmarking and fidelity response theory of high-fidelity Rydberg entangling gates
• Controlling two-dimensional Coulomb crystals of more than 100 ions in a monolithic radio-frequency trap
• Fault-tolerant quantum computation using large spin cat-codes
• Universal Set of Gates for Microwave Dressed-State Quantum Computing
• Coherent excitation of a $\mu$Hz scale optical magnetic quadrupole transition
• Minutes-scale Schr{ö}dinger-cat state of spin-5/2 atoms

Cited by in corpus (1)

• High-resolution spectroscopy of 162Dy Rydberg levels