Sumiran Pujari
Associate Professor
Photograph: 
Phone: 
(+91) 22-2576-9376
Email: 
sumiran@phy.iitb.ac.in
sumiran.pujari@iitb.ac.in
Fax Number: 
Sometimes I may not reply within a reasonable time period due to wrong spam filing by the institute email server if it sees it coming from a new email address. If there is such a suspicion, please write to my gmail with handle "first name dot last name".
Office: 

221 Physics

Research Interests: 
  • Condensed Matter Theory
  • Quantum Magnetism
  • Algorithms
  • Exactly solvable models

Current group members:

  • Anoop Raj, Ph. D. candidate, 2022- -- Coulomb phases in classical dimer models
  • Sankalp Kumar, Ph. D. candidate, 2021- --  Quantum phase transitions in SU(N) magnets
  • Naba Prakash Nayak, Ph. D. candidate, 2019- -- Disorder driven quantum phase transitions (primarily supervised by Soumya Bera)
  • Vikas Vijigiri, Institute post-doc, 2021-2023  -- Deconfined criticality in S=1 Hamiltonians

Past group members:

  • Saumitra Jain, Civil Engg., Ph.D., 2017-2022 -- Periodic Metamaterial based seismic isolation of structures (co-supervised with Arghadeep Laskar, Civil Engg.)
  • Tannistha Gupta, M. Phil exit, 2018-2022
  • Santanu Pal, Institute post-doc, 2019-2021 -- Colouring wavefunctions for quantum magnets

Notable UG/PG collaborators:

  • Vedant Motamarri, B.Tech+M.Tech, 2021-2022 -- Loop ensembles in Stochastic Series Expansion of Two-Dimensional Heisenberg Antiferromagnets
  • Abhishek Kejriwal, B.Tech+M.Tech, 2020-2023 -- Spin dynamics in Nitrogen vacancy centers in Diamond (co-supervised with Kasturi Saha, Elec. Engg.)
  • Sudipta Borah, M.Sc, 2020-2021 -- Study of edge modes in models with higher topological invariants
  • Vineet Punyamoorty, Elec. Engg., B.Tech+M.Tech, 2020-2021 -- Flux-flow Hall effect in superconductors using Time-Dependent Ginzburg-Landau Equations (co-supervised with Kasturi Saha, Elec. Engg.)
Selected Publications: 
  • Deconfined pseudocriticality in a model spin-1 quantum antiferromagnet,
    arXiv:2307.14254
    Related slides here by N. Desai.

  • A class of exactly solvable Hamiltonians for S=1/2 quantum magnets
    with spinless fermionic excitations in higher dimensions,
    ResearchGate (being prepared for arXiv upload)
    Related slides here with supporting data. Material realization for this
    class of models with bond-dependent couplings seems feasible.

  • Punctured-Chern topological invariants for semi-metallic bandstructures, 
    Phys. Rev. Lett. 130, 186202 (2023), arXiv:2205.07814
    Related slides here. These invariants could be useful for anyone interested
    in band topology in presence of gap-closing points.

  • Unusual spin dynamics in the low-temperature magnetically ordered state of Ag_3 Li Ir_2 O_6
    Phys. Rev. B 104, 115106 (2021), arXiv:2104.10057
    Related slides here that discuss the well-known (or perhaps little-known)
    issue about large muon relaxation rates in some ordered antiferromagnets
    (e.g. Gd_2 Sn_2 O_7 and also Ag_3 Li Ir_2 O_6) comparable to that of many
    spin liquid candidate materials.
  • Resummation-based quantum Monte Carlo for quantum paramagnetic phases
    Phys. Rev. B 104, L060406 (2021), arXiv:2104.06792
    Related seminar video here and slides here.
  • Bilayer Coulomb phase of two dimensional dimer models: Absence of power-law columnar order
    Phys. Rev. E 103, 042136 (2021), arXiv:2011.04506 
    Related seminar video here and slides here.
  • Gapless quantum spin liquid in the triangular system Sr_3 Cu Sb_ 2 O_9
    Phys. Rev. Lett. 125, 267202 (2020), arXiv:2012.01239 
    Related colloquium-style seminar video here and slides here.
  • Topological character of three-dimensional Nexus triple point degeneracies
    Phys. Rev. B 102, 235148 (2020),  arXiv:2006.00709 
    Related seminar video here and slides here.
    (a seminar video here and slides here on a previous work which was instrumental for this work.)
  • Resonating three-coloring wavefunctions for the kagome quantum antiferromagnet
    Phys. Rev. B 99, 104433 (2019), arXiv:1808.08633 
    Related seminar video here and slides here.
 
  • Interaction induced Dirac fermions in bilayer graphene
    Phys. Rev. Lett. 117, 086404 (2016), arXiv:1604.03876 
    Related slides here. (These slides contain unpublished results on SU(N>2) on-site
    Hubbard model on Bernal-stacked honeycomb bilayer, while the paper focused on
    SU(2). In short, for SU(4) there is a continuous quantum phase transition from a
    Dirac liquid to a Neél antiferromagnet similar to SU(2), while for SU(6) (and greater)
    there is a strong first-order transtion from the Dirac liquid to a valence bond solid.)
  • Sign-problem-free Monte Carlo simulation of certain frustrated quantum magnets
    Phys. Rev. Lett. 117, 197203 (2016), arXiv:1511.01586 
    Related slides here by F. Alet.
  • Transitions to valence-bond solid order in a honeycomb lattice antiferromagnet
    Phys. Rev. B 91, 104411 (2015), arXiv:1502.01035   
    Related slides here.
------------------------------------------- Puerile Ph.D. Phase ---------------------------------------------
 
  • Emergent spin excitations in a Bethe lattice at percolation
    Phys. Rev. Lett. 111, 157201 (2013), arXiv:1210.4621 
  • "Inversion" techniques for Scanning Tunneling Microscopy data analyses
    Ph. D. Thesis (2011)
    Related slides here and thesis document here.

Most of my publications are listed at : https://arxiv.org/a/pujari_s_1.html

A few papers resulting through collaborations in the engineering discipline are not in this list.

Extensive collaborations:

  • Ankur Das (2018-now)
  • Nisheeta Desai (2016-now)
  • Avinash Majahan (2018-now)
  • Kedar Damle (2019-2020, 2016-2017 (as postdoc mentor), 2011-2014 (as postdoc mentor))
  • Hitesh Changlani (2017-2021, 2008-2011)
  • Christopher Henley (2012-2013, 2006-2011 (as Ph.D. guide))

Other past collaborators:

Teaching history:

  • 2023-24/1 PH 251 - Classical Mechanics (minor)
  • 2023, Tutor for summer school on the physics of quantum matter
  • 2021-22/2 PH 554 : Computational Many-body Physics
  • 2021-22/1 PH 217 : Classical Mechanics
  • 2021-22/2 PH 554 : Computational Many-body Physics
  • 2021-22/1 PH 401 : Classical Mechanics
  • 2020-21/2 PH 410 : Statistical Physics
  • 2020-21/1 PH 401 : Classical Mechanics
  • 2019-20/2 PH 438 : Statistical Physics
  • 2019-20/1 PH 217 : Classical Mechanics
  • 2018-19/2 PH 310 : Introduction to Condensed Matter Physics
  • 2018-19/1 PH 409 : Introduction to Condensed Matter Physics
  • 2017-18/2 EP 320 (now PH 438) Statistical Physics
  • 2017-18/1 PH 409 : Introduction to Condensed Matter Physics 

Miscellaneous:

  • a general talk video here given to IIT Bombay community on convocation-2020 speaker F. D. M. Haldane's Nobel prize winning work
  • slides on an outreach talk here on "Differential Equations in Science and Engineering" given at Sharad Chandra ACS College, Naigaon, Nanded, Maharashtra on Feb, 2020
  • some other writings here

Worldline:

  • 1983: Sambalpur, Odisha (birth, P. K. Pujari (retired engineer, RSP), A. Pati (retired senior reader)) 
  • 1983-2001: Rourkela, Odisha (childhood and schooling)
  • 2001-2005: Mumbai (undergraduate)
  • 2005-2011: Ithaca, NY, USA (Ph.D. training)
  • 2011-2014: Toulouse, France (postdoc)
  • 2014-2016: Lexington, KY, USA (postdoc)
  • 2016-now: Mumbai
Research Category: 
Condensed Matter Theory