Research

Semiconducting quantum dot qubits have received significant attention over the last few years due to their scalability and improved coherence times. It is still a challenging problem to find the appropriate computational subspace for a single qubit in a coupled multi-dot device. My research in this field involves devising theoretical techniques to construct a quantum dot qubit as well as finding robust procedures to perform high-fidelity logical quantum gate operations in such qubits.

Selected relevant publications:

1. Physical Review B [Rapid Communication], 95, 241307(R) (2017)

2. Nature Communications, 8, 15923 (2017)

Recent years have witnessed remarkable progress in quantum computing with superconducting devices, such as transmon qubits and superconducting microwave resonators. With recent advances in designing scalable qubits and high-fidelity single- and two-qubit quantum gates, a major focus now is on the Fault-Tolerant Quantum Computing (FTQC) with superconducting components as hardware and Topological Quantum Error Correction (TQEC) as software. The two dominant sources of error in superconducting quantum computing are decoherence (tunneling of quantum information to the environment) and leakage (tunneling of quantum information from the computational subspace to the Hilbert space of the entire system). It has been demonstrated recently that decoherence can be enormously suppressed with modern superconducting qubits (e.g., Xmon qubits), while leakage remains a prominent obstruction towards FTQC with superconducting components. The main goal of this research is to understand the role of leakage as well as devise leakage-resilient schemes for FTQC that can be realized in superconducting circuits under experimental conditions.

Selected relevant publications:

1. Physical Review A [Rapid Communication], 91, 020302(R) (2015)

2. Physical Review A, 88, 062329 (2013)

3. Physical Review A, 86, 062318 (2012)

Superconducting qubits, with their long coherence times and high degree of scalability, offer a perfect platform for simulating/emulating other quantum phenomena, such as quantum transport, quantum chaos, interaction between photons and multi-level atoms etc. The primary objective of this research is to develop realistic schemes for quantum simulation/emulation that can be implemented with promising superconducting circuits.

Selected relevant publications:

1. New Journal of Physics, 18, 033015 (2016)

2. Physical Review A, 90, 062318 (2014)

3. Physical Review A, 89, 022309 (2014)

Optimal quantum control is essential for designing high-fidelity quantum operations required for Fault-Tolerant Quantum Computing (FTQC). The main goal of this research is to develop novel quantum control strategies to design optimal pulse sequences for some target quantum operations under realistic constraints.

Selected relevant publications:

1. Physical Review Letters, 114, 200502 (2015)

2. Physical Review Applied, 6, 054005 (2016)