Key facts
- IBM announced three new methods to demonstrate quantum advantage on current quantum hardware.
- These methods address the challenge of verifying quantum computer results when classical simulations are infeasible.
- One approach involved modeling a Floquet process and an Ising model, with results cross-verified on different quantum processors.
- Another method utilized Clifford gates with T gates for error detection and fidelity certification.
- A third method used a quantum echoes technique to detect errors and verify results.
Demonstrating the capabilities of quantum computers on today's noisy and limited hardware presents a significant challenge, particularly in verifying results that are beyond the reach of classical computers. IBM has introduced three new approaches to tackle this issue, aiming to establish quantum advantage.
One of the new efforts, a collaboration between IBM, RIKEN, and Qedma, focused on modeling a Floquet process and an Ising model. This involved running classical algorithms on the Fugaku supercomputer to identify discrepancies, then comparing these with results from an IBM quantum processor using Qedma's error-mitigation software. The quantum processor showed a gradual decrease in magnetism with periodic oscillations, which differed from the classical simulations. To further validate, the team used a Quantinuum processor and identified a potential issue in one of the quantum algorithms related to truncating terms.
A second approach, developed by IBM and researchers at the University of Chicago, involves running variations of an algorithm multiple times. This method incorporates Clifford gates, which are easier to simulate classically, but strategically includes non-Clifford T gates to increase the complexity for classical simulation. The algorithm also uses additional qubits for error detection, discarding results if errors are flagged.
The third initiative comes from quantum software developer Algorithmiq, utilizing an algorithm similar to Google's "quantum echoes" work. This process involves altering a quantum system, reversing it, and using additional operations to create an imperfect "echo" of the forward process due to noise. Simulating this on classical hardware is challenging.