William Witczak-Krempa

Research Interests

I'm a condensed matter theorist interested in quantum many-body physics at large, notably in the 'strongly-correlated' regime. My main subjects of study are quantum criticality (including conformal field theory), quantum spin liquids, and the interplay between topology and symmetry in quantum phases, especially symmetry protected topological order. In the latter case, this connects to quantum materials involving strong spin-orbit coupling and interactions.
I use various tools including quantum field theory, lattice Hamiltonians (Hubbard/spin models), numerical variational methods, and the AdS/CFT holographic correspondence. I also collaborate extensively with numerical experts that specialize in Quantum Monte Carlo and cluster methods such as Dynamical Mean Field Theory or Cluster Perturbation Theory.
If you are curious, take a look at my full list of publications. The most recent ones are shown below.

I co-authored a review article about correlated quantum phenomena in the strong spin-orbit regime (arXiv version).

My PhD thesis can be found here.

Awards

• Walter Sumner Fellowship
• NSERC Michael Smith Foreign Study Supplement - held at MIT
• NSERC Alexander Graham Bell CGS Doctoral Fellowship
• Anne Molson Gold Medal in Mathematics, McGill University
• Horace Watson Gold Medal in Physics, McGill University

Recent Publications

• Emanuel Katz, Subir Sachdev, Erik S. Sorensen, William Witczak-Krempa, "Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography", Phys. Rev. B 90, 1 December 2014, 245109, Editor's Suggestion, arXiv: 1409.3841
• William Witczak-Krempa, Michael Knap, Dmitry Abanin, "Interacting Weyl semimetals: Characterization via the topological Hamiltonian and its breakdown", Phys. Rev. Lett. 113, September 2014, 136402, arXiv: 1406.0843
• William Witczak-Krempa, "Quantum critical charge response from higher derivatives in holography", Phys. Rev. B, 89, April 2014, 161114(R), arXiv: 1312.3334
• William Witczak-Krempa, Gang Chen, Yong Baek Kim, Leon Balents, "Correlated quantum phenomena in the strong spin-orbit regime", Annual Reviews of Condensed Matter Physics, 5, March 2014, 57-82, arXiv: 1305.2193
• William Witczak-Krempa, Erik Sorensen, Subir Sachdev, "The dynamics of quantum criticality revealed by quantum Monte Carlo and holography", Nature Physics 10, March 2014, 361-366, arXiv: 1309.2941
• William Witczak-Krempa, Ara Go, Yong Baek Kim, "Pyrochlore electrons under pressure, heat and field: shedding light on the iridates", Phys. Rev. B, 87, April 2013, 155101, arXiv: 1208.4099
• William Witczak-Krempa, Subir Sachdev, "Dispersing quasinormal modes in 2+1 dimensional conformal field theories", Phys. Rev. B, 87, 29 April 2013, 155149, Editor's Suggestion, arXiv: 1302.0847
• William Witczak-Krempa, Subir Sachdev, "The quasinormal modes of quantum criticality", Phys. Rev. B, 86, 12 December 2012, 235115, arXiv: 1210.4166
• "Constraining quantum critical dynamics: 2+1D Ising model and beyond", W. Witczak-Krempa, arXiv: 1501.03495

Seminars

• "Fluides critiques quantiques", Université de Montréal, Montréal, Canada.
• "Constraining Quantum Critical Dynamics: 2+1D Ising Model & Beyond", Caltech, Pasadena, US.
• "Constraining Quantum Critical Dynamics: 2+1D Ising Model & Beyond", Kavli Institute for Theoretical Physics, Santa Barbara, US, Video recording
• "Constraining Quantum Critical Dynamics: 2+1D Ising Model & Beyond", University of California Berkeley, Berkeley, US.
• "Quantum critical dynamics without quasiparticles", Review Meeting: Multi-University-Research-Initiative on Fundamental Issues in Non-Equilibrium Dynamics, Rice University, TX, US
• "The dynamics of CFTs at finite temperature", Entangled, Quantum Matter, and Topology (PI-UIUC Workshop), University of Illinois at Urbana Champaign
• "Correlated quantum phenomena in the strong spin-orbit regime", Université de Montréal, Montréal, Canada. [in French]
• "Correlated quantum phenomena in the strong spin-orbit regime", Université de Sherbrooke, Sherbrooke, Canada. [in French]
• "Interacting Weyl semimetals: Characterization via the topological Hamiltonian and its breakdown", Max Plank Institute for Complex Systems, Dresden, Germany
• "The dynamics of quantum criticality: Quantum Monte Carlo and holography", APS March Meeting 2014, Denver, US
• "The dynamics of quantum criticality: Quantum Monte Carlo and holography", Princeton Center for Theoretical Science, Princeton, US
• "The dynamics of quantum criticality: Quantum Monte Carlo and holography", Aspen winter conference 'Beyond quasiparticles', Aspen, US
• "The dynamics of quantum criticality: Quantum Monte Carlo and holography", University of Chicago, Chicago, IL, US
• "Correlated quantum phenomena in the strong spin-orbit regime", McGill University, Montreal, QC, Canada
• "The dynamics of quantum criticality: Quantum Monte Carlo and holography", Harvard University, Cambridge, MA, US
• "Correlated quantum phenomena in the strong spin-orbit regime", Harvard University, Cambridge, MA, US
• "Holographic insights into quantum critical transport: from branes to Bose-Hubbard", Workshop and Conference on Geometrical Aspects of Quantum States in Condensed Matter, ICTP, Trieste, Italy
• "Holographic insights into quantum criticality: from black holes to Bose-Hubbard", King's College London, London, UK
• "Interaction effects on 3D topological insulators and semi-metals", APS March Meeting 2013, Baltimore, US [Invited symposium talk]
• "The quasi-normal modes of quantum criticality", APS March Meeting 2013, Baltimore, US
• "The conductivity of CFTs from a holographic viewpoint", University of Illinois Urbana-Champaign, Urbana-Champaign, US
• PIRSA:14090072, Conformal field theories at non-zero temperature: operator product expansions, Monte Carlo, and holography, 2014-09-19, Condensed Matter
• PIRSA:13050037, Holographic insights into quantum critical transport: from branes to Bose-Hubbard, 2013-05-08, Emergence & Entanglement II 2013
• "Holography and quantum criticality", Condensed matter group meeting, Perimeter Institute, Waterloo, Canada
• "Quasinormal modes of quantum criticality", Holography group meeting, Perimeter Institute, Waterloo, Canada
• PIRSA:11120075, Interactions and Spin Orbit: from Weyls to Helical Spin Liquids, 2011-12-08, Condensed Matter