New Quantum Cooling Method Promises Efficient Computing
Scientists at the University of California, Santa Barbara, have developed a novel method for cooling quantum systems. The Double-Bracket Algorithmic Cooling (DBAC) technique, led by Prof. John Martinis, has been experimentally validated on a superconducting qubit lattice, showing promise in reducing quantum coherence.
DBAC simulates quantum imaginary-time evolution through a process called recursive unitary synthesis of Riemannian steepest-descent flows. Unlike established protocols like HBAC, DBAC is more experimentally accessible, requiring fewer gates and avoiding initial dephasing steps. This makes it a practical solution for cooling operations.
DBAC can reduce quantum coherence in isolated ensembles, such as nuclear spins in molecules or nitrogen-vacancy centers in diamonds. It mimics imaginary-time evolution, driving a quantum state towards its ground state. Notably, its performance scales with the number of input qubits. The method uses density-matrix exponentiation as a subroutine and operates using quantum information stored in copies of the input states. It also operates 'on the fly', programming cooling dynamics with input qubits and eliminating the need for mid-circuit measurements.
The research group's work opens up new avenues for quantum entropy problem solving. Future research will focus on optimizing DBAC's circuit depth and pulse fidelity for improved efficiency and application to complex quantum systems. This could pave the way for more efficient quantum computing and enhanced understanding of quantum systems.
