**Quantum Information & Computation, Quantum Optics, and Condensed Matter****(Theory)**

###### Research Overview

My field of interest is Quantum Information & Quantum Computation and its intersection with Condensed Matter Physics and Quantum Optics (light-matter interaction). I am primarily interested in foundations of quantum theory, correlations (entanglement), open systems & decoherence, near term quantum algorithms and protocols, architecture of quantum computing (via graph theory and distributed approach) and realization of quantum information processing (QIP) via cavity/circuit-QED, ion traps, and topological matter. Condensed Matter aspects such as correlated quantum matter, magnetism in quantum theory and many-body systems also concern my interest. Quantum optics aspects of my interests include light-matter interaction which is very well exploited for QIP via cavity-QED theory, and measurements in quantum optics. More details topic-wise is given below.

###### Quantum Information and

Quantum Computing

- Architecture of quantum computers, especially the approach of distributed quantum computing. Alternative approaches in monolithic architectures using graph theory (perfect transfer schemes and architectures)
- Quantum Error Correction (QEC) protocols (general correction codes, topological codes, surface codes, etc.) for near term NISQ (Noisy Intermediate Scale Quantum) quantum computers
- Theory of entanglement and general correlations for many-qubit system and mixed states, and entanglement purification
- Quantum Communication over noisy channels
- Development of quantum algorithms for problems in linear algebra (hybrid quantum-classical and variational algorithms) for near term devices and long term scalable quantum technology
- Quantum programming, testing, and benchmarking in variety of platforms and hardware implementations (IBM Qiskit, Rigetti systems, Xanadu Pennylane, Microsoft Q#, IonQ, and adiabatic annealer(s) – DWave)
- [Learning] Quantum Machine learning and advanced numerics for large scale simulations

###### Quantum Optics

- Light matter interaction over different coupling regimes (Jaynes-Tavis-Cummings, approximations, strong and ultrastrong coupling)
- Cavity quantumelectrodynamics (Cavity-QED) and Circuit-QED (superconducting qubit architecture)
- Open Quantum Systems (Master Equations, Lindbladian, Quantum Langevin Equations (QLEs)) in Markovian and non-Born-Markovian systems
- Design of superconducting quantum circuits (SQCs) and scalable architecture with waveguide-QED systems (including chiral quantum networks)
- Input/Output theory in circuit-QED
- Theory of quantum decoherence in complex quantum systems
- Ion-trap theory and quantum optics of the QIP implementation with NV-centre

###### Condensed Matter

- Topology in condensed matter systems (Quantum fractional Hall effect and further)
- Quantum Annealing (QA) with Ising and Heisenberg models with various coupling and connectivity configurations
- Quantum many-body physics
- Magnetism in complex systems
- Many-body Hamiltonians in 1+ dimensions (Hubbard, Anderson, Haldane, etc.)
- Berry phases, geometric phases, and topological phases in condensed matter systems
- [non-expertise] Topological Quantum Computing with anyons

© Siddhant Singh, 2020