Photon recoil and laser focusing limits to Rydberg gate fidelity

Abstract

Limits to Rydberg gate fidelity that arise from the entanglement of internal states of neutral atoms with the motional degrees of freedom due to the momentum kick from photon absorption and re-emission is quantified. This occurs when the atom is in a superposition of internal states but only one of these states is manipulated by visible or UV photons. The Schrödinger equation that describes this situation is presented and two cases are explored. In the first case, the entanglement arises because the spatial wave function shifts due to the separation in time between excitation and stimulated emission. For neutral atoms in a harmonic trap, the decoherence can be expressed within a sudden approximation when the duration of the laser pulses are shorter than the harmonic oscillator period. In this limit, the decoherence is given by simple analytic formulas that account for the momentum of the photon, the temperature of the atoms, the harmonic oscillator frequency, and atomic mass. In the second case, there is a reduction in gate fidelity because the photons causing absorption and stimulated emission are in focused beam modes. This leads to a dependence of the optically induced changes in the internal states on the center of mass atomic position. In the limit where the time between pulses is short, the decoherence can be expressed as a simple analytic formula involving the laser waist, temperature of the atoms, the trap frequency and the atomic mass. These limits on gate fidelity are studied for the standard $\pi -2\pi -\pi$ Rydberg gate and a new protocol based on a single adiabatic pulse with Gaussian envelope.

8 figures

References in corpus (8)

• Quantum computing with trapped ions
• An atom-by-atom assembler of defect-free arbitrary 2d atomic arrays
• Quasiclassical calculations of BBR-induced depopulation rates and effective lifetimes of Rydberg nS, nP and nD alkali-metal atoms with n < 80
• Consequences of Zeeman Degeneracy for van der Waals Blockade between Rydberg Atoms
• High-fidelity Rydberg quantum gate via a two-atom dark state
• Robust quantum logic in neutral atoms via adiabatic Rydberg dressing
• Coherence preservation of a single neutral atom qubit transferred between magic-intensity optical traps
• Entanglement dynamics of a strongly driven trapped atom

Cited by in corpus (28)

• Demonstration of multi-qubit entanglement and algorithms on a programmable neutral atom quantum computer
• High-fidelity parallel entangling gates on a neutral atom quantum computer
• Quantum Computing with Circular Rydberg Atoms
• Quantum logic and entanglement by neutral Rydberg atoms: methods and fidelity
• Optimizing Rydberg Gates for Logical Qubit Performance
• High-fidelity interconversion between Greenberger-Horne-Zeilinger and $W$ states through Floquet-Lindblad engineering in Rydberg atom arrays
• Rabi-error and Blockade-error-resilient All-Geometric Rydberg Quantum Gates
• Architecture for fast implementation of qLDPC codes with optimized Rydberg gates
• Neutral atom entanglement using adiabatic Rydberg dressing
• Hyperentanglement of divalent neutral atoms by Rydberg blockade
• Geometric quantum gates via dark paths in Rydberg atoms
• Shortcut-to-Adiabatic Controlled-Phase Gate in Rydberg Atoms
• Fast entangling gates for Rydberg atoms via resonant dipole-dipole interaction
• Motional decoherence in ultracold Rydberg atom quantum simulators of spin models
• Coherent spin-phonon scattering in facilitated Rydberg lattices
• Suppression of motional dephasing using state mapping
• Preparing Greenberger-Horne-Zeilinger state on ground levels of neutral atoms
• The iSWAP gate with polar molecules: Robustness criteria for entangling operations
• Resonant stroboscopic Rydberg dressing: electron-motion coupling and multi-body interactions
• Nanoscale addressing and manipulation of neutral atoms using electromagnetically induced transparency
• Error-budgeting for a controlled-phase gate with strontium-88 Rydberg atoms
• Multi-Qubit Parity Gates for Rydberg Atoms in Various Configurations
• Time-Optimal Two- and Three-Qubit Gates for Rydberg Atoms
• Probing spin-motion coupling of two Rydberg atoms by a Stern-Gerlach-like experiment
• Barium-based Rydberg atom quantum technologies with long Rydberg coherence
• Isotope-agnostic motional ground-state cooling of neutral Yb atoms
• Symmetric $C_Z$ gate for ultracold neutral atoms based on counterdiabatic driving at Rydberg excitation
• All-to-all connectivity of Rydberg-atom-based quantum processors with messenger qubits