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Amulya Ratnakar

Amulya Ratnakar

Research Scholar
Course : Ph.D. (UGC-NET)
Research Guide:
Sourin Das
    Location: RC, N-102, DPS, IISER Kolkata
    Email: ar18rs084[ at ]iiserkol.ac.in
    Tel:

Research group

Research areas

  • Quantum physics at low dimensions :- Luttinger Liquids (Quantum wires, Edge states of Quantum Hall system etc.), Bosonization, fractional Josephson effect

Currently, I am interested in the low-dimensional interacting electronic systems, which are described by the universal Luttinger liquid (LL) model. The physics of LLs is fascinating because they exhibit non-fermi liquid behavior in the sense that there are no electron-like quasi-particles in the low energy excitation spectrum of the theory. The low-energy excitations that are present are bosonic in nature and as such, we use the Bosonization technique to describe the low-energy physics of LLs. Quantum wires (QWs) and Edge states of fractional and integer quantum Hall (QH) systems are among the physical system which can be described by the LL model. The junction of LL QWs have attracted considerable attention in recent years due to their applicability as the basic building blocks of quantum circuits and hence our interest in studying the junction of multiple LLs either with themselves or with other phases of matter. The effect of inter-electron interaction and strong correlations arising in the vicinity of such junction can give rise to interesting phenomenon like unexpected enhancement in local tunneling density of states (TDOS) in the zero-bias limit, spin-charge separation, charge fractionalization etc. These effects can be probed via tunneling experiments and multi-terminal AC conductivity measurements and can be theoretically analyzed using Bosonization technique. Recently, we are also studying the junction of helical edge states of QH system proximitized by s-wave superconductor in the Josephson Junction (JJ) context which may give rise to the fractional Josephson effect due to Z_{2m} parafermion zero mode present in the system.

  • Integrated M.Sc. (2012 - 2017, 7.71 GPA , UM-DAE CEBS (2012-2017))
  • AISSCE (12th), 2011, 85.6%
  • AISSE (10th), 2009, 92%
  • UGC-CSIR NET (2017)
  • INSPIRE Fellowship (2012-2017)
  1. Spontaneous fractional Josephson current from parafermions ( arXiv:2208.05504 )
  2. Tunneling density of states in a Luttinger liquid in proximity to a superconductor: Effect of nonlocal interaction. (Phys. Rev. B 106, 115412 (2022))
  3. Enhancement in tunneling density of states in a Luttinger liquid: Role of nonlocal interaction. (Phys. Rev. B 104, 045402 (2021))
  4. Dimensional cross-over in self-organised super-radiant phases of ultra-cold atoms inside a cavity. (Journal of Physics B: Atomic, Molecular and Optical Physics. (2022))
  5. Two-particle spectral function for disordered s-wave superconductors: Local maps and collective modes. (Phys. Rev. B 101, 024507 (2020))
  6. Landau Level Diagram and the Continuous Rotational Symmetry Breaking in Trilayer Graphene. (Phys. Rev. Lett. 121, 056801 (2018))
  • Teaching Assistant :- Electricity and Magnetism, Spring 2019
  • Teaching Assistant, Quantum Many Body Theory, Spring 2023