Noise-resilient Universal Quantum Computing in the Presence of Anisotropic Noise

Abstract

We propose a universal gate set for quantum computing that operates in the presence of decoherence without the overhead of active error correction. We show that a broad class of anisotropic system--bath couplings can be effectively decoupled by preparing an appropriate system--bath entangled initial state. The initially established entanglement serves as a resource to cancel out the dominant decoherence during evolution, enabling quantum computation to proceed as if the system were effective decoupled from its environment.

Figures (3)

• Figure 1: Representative random pure state on the Bloch sphere, used as the initial condition for fidelity evaluation. The results are qualitatively independent of the specific initial state.
• Figure 2: Fidelity $F$ vs. coupling strength $|\alpha|$ for bosonic frequencies $\omega_b = 0.1$ (sub-resonant), 2.0 (resonant), and 10.0 (super-resonant) at fixed system frequency $\omega_0 = 2$. High fidelity is maintained for small $|\alpha|$ across all cases, while the resonant case exhibits the most pronounced decay. These results delineate the parameter regime in which the dressing transformation remains accurate.
• Figure 3: Infidelity $1-F$ versus evolution time $t$ for different anisotropy deviations $\delta\lambda$, at resonance $\omega_0=\omega_b=2$ and with coupling strength $|\alpha|=0.01$. The curves nearly overlap, indicating that small deviations from the ideal anisotropy have little effect on the fidelity decay and only a negligible effect on the corresponding tolerance timescale in the weak-coupling regime.