Hi all,
Tomorrow Tenzan Araki will tell us about their Masterthesis at IBM entitled "Simulating open quantum systems via noise engineering on superconducting quantum computers". See below for the abstract. The talk will take place at 4pm in HIT E 41.1.
Best, Ladina
Title:
Simulating open quantum systems via noise engineering on superconducting quantum computers
Abstract:
While quantum gates in a gate-based quantum computer are unitary, quantum computers can also be used to simulate open quantum systems, enabling the description of real-life quantum systems that interact with an environment. Despite the importance of understanding open quantum systems, their classical simulation is generally harder than that of closed quantum systems. Therefore, using quantum computers to simulate open quantum system dynamics is considered a possible use case to demonstrate practical quantum advantage. To this end, studies have commonly combined unitary quantum gates with non-unitary operations that utilize ancilla qubits and measurements to simulate the irreversible dissipative dynamics. However, the noise that is present in today’s quantum computers remains an obstacle that limits the fidelity of such simulation. Independently, a line of work known as "noise engineering" attempts to perform tasks on quantum systems through engineering the noisy environment coupled to them. Instead of attempting to protect qubits, this approach accepts the presence of noise and tries to utilize it as a resource.
In this work, we simulate the dynamics of an open quantum system by an ancilla-free noise engineering approach. Instead of mimicking the environment with ancilla qubits, the noise spectral function acted on each qubit are controlled through fluctuations in the photon number of the readout resonator coupled to the qubit. An open quantum system is then simulated by Trotterization, similarly to how many closed quantum system dynamics are simulated, but with additional non-unitary gates corresponding to the dissipative channels that are controlled through noise engineering. In this talk, we introduce the theory behind this implementation using the dissipative Ising model as an example, and discuss progress in hardware demonstrations on the superconducting quantum devices provided by IBM Quantum.