Measurement-Based Long-Range Entangling Gates in Constant Depth

Abstract

The depth of quantum circuits is a critical factor when running them on state-of-the-art quantum devices due to their limited coherence times. Reducing circuit depth decreases noise in near-term quantum computations and reduces overall computation time, thus, also benefiting fault-tolerant quantum computations. Here, we show how to reduce the depth of quantum sub-routines that typically scale linearly with the number of qubits, such as quantum fan-out and long-range CNOT gates, to a constant depth using mid-circuit measurements and feed-forward operations, while only requiring a 1D line topology. We compare our protocols with existing ones to highlight their advantages. Additionally, we verify the feasibility by implementing the measurement-based quantum fan-out gate and long-range CNOT gate on real quantum hardware, demonstrating significant improvements over their unitary implementations.

6 pages, 8 figures (main text) + 5 pages, 7 figures (appendix)

References in corpus (16)

• Dynamical Decoupling of Open Quantum Systems
• A simple formula for the average gate fidelity of a quantum dynamical operation
• Direct Fidelity Estimation from Few Pauli Measurements
• Quantum algorithms for electronic structure calculations: particle/hole Hamiltonian and optimized wavefunction expansions
• Practical characterization of quantum devices without tomography
• Efficient Long-Range Entanglement using Dynamic Circuits
• Preparation of matrix product states with log-depth quantum circuits
• Quantum Circuits with Unbounded Fan-out
• Topological Order from Measurements and Feed-Forward on a Trapped Ion Quantum Computer
• Constant-depth preparation of matrix product states with adaptive quantum circuits
• Approximating many-body quantum states with quantum circuits and measurements
• State preparation by shallow circuits using feed forward
• Realizing the Nishimori transition across the error threshold for constant-depth quantum circuits
• Multivariate trace estimation in constant quantum depth
• Characterizing MPS and PEPS Preparable via Measurement and Feedback
• A 2D Nearest-Neighbor Quantum Architecture for Factoring in Polylogarithmic Depth

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• Efficient Generation of Multi-partite Entanglement between Non-local Superconducting Qubits using Classical Feedback
• Minimally Universal Parity Quantum Computing
• A recipe for local simulation of strongly-correlated fermionic matter on quantum computers: the 2D Fermi-Hubbard model
• Exploration of Design Alternatives for Reducing Idle Time in Shor's Algorithm: A Study on Monolithic and Distributed Quantum Systems
• Simple ways of preparing qudit Dicke states
• Enhancing quantum computations with the synergy of auxiliary field quantum Monte Carlo and computational basis tomography
• Resource-Efficient Quantum Optimization via Higher-Order Encoding
• Long-ranged gates in quantum computation architectures with limited connectivity
• Error Mitigation in Dynamic Circuits for Hamiltonian Simulation
• Measurement-Driven Adaptive Low-Overhead Implementation of Multi-Controlled Toffoli Gates
• Quantum Circuits for Matrix-Product Unitaries
• Measurement-and Feedback-Driven Non-Equilibrium Phase Transitions on a Quantum Processor
• Linear optical fan-out gates using fewer ancillary single photons with enhanced success probability