Research
Multi-qubit gates with trapped ultracold atoms
A Hamiltonian in many-body physics typically acts non-trivially on >2 (if not all) qubits. Unitaries generated by such Hamiltonians are multi-qubit gates. The goal of this project is to experimentally develop, benchmark, and error-mitigate multi-qubit gates.
The case for multi-qubit gates is that they can be directly useful, as in the case of studying many-body physics and indirectly useful for e.g, they can be used to develop alternate, simpler circuits to implement quantum algorithms. Although all multi-qubit gates can be generated using one and two qubits gates, for e.g using trotterization, this method is not necessarily error-efficient. Therefore, developing experimental application of multi qubit gates using new physical processes is desirable. Figure on the left shows application of a multi-qubit plaquette gate on a desired subset of qubits trapped in optical tweezers. See Developing multi-qubit gates for more details.
Benchmarking and error mitigation for multi-qubit gates
The standard techniques of benchmarking and error mitigation are suitable for one and two-qubit gates, or for random circuits. Congenial to the above project pon developing multi-qubit gates, it is desirable to develop new benchmarking and error mitigation schemes for multi-qubit gates. Some work in this direction is already in progress (see this paper and this paper). See Developing multi-qubit gates for more details.
Metrological enhancement in qubit readout
Two of the most common forms of errors in quantum control are state preparation errors and measurement errors, together known as SPAM errors. The goal of this project is to apply ideas from quantum metrology into state preparation and readout in order to decrease SPAM errors. The foundations to this idea have been developed recently.
Solving many-body problems on analog quantum simulators
Quantum certified approximations (QCA) is a recently developed application of near term quantum computers and simulators. Although the Hilbert space dimension of a many-body system scales exponentially in its system size, many of its properties, including equilibrium properties and time dynamics are often approximable, i.e., there exist efficient classical approximation algorithms. However, it is not necessarily straightforward to find an efficient approximation. A near-term, noisy quantum computer can help us find an ansatz that could lead us to an efficient approximation (see figure on the right). See Applications to many-body physics for details.
