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Subir Sachdev

Portrait de Subir Sachdev
Cenovus Energy James Clerk Maxwell Chair in Theoretical Physics at Perimeter Institute (Visiting)

Area of Research:

Subir Sachdev of Harvard University has made prolific contributions to quantum condensed matter physics, including research on quantum phase transitions and their application to correlated electron materials like high temperature superconductors. In recent years, Sachdev has exploited a remarkable connection between the electronic properties of materials near a quantum phase transition and the quantum theory of black holes. His 1999 book, Quantum Phase Transitions, has been described as "required reading for any budding theorist."

Past PI Talks:
•    “Quantum criticality and black holes”: http://pirsa.org/08040006
•    “Nodal Quasiparticles and Spin and Charge Order in the Cuprate Superconductors”: http://pirsa.org/08040031.
•    All of Prof. Sachdev’s past PI research talks may be viewed here.

Research Interests

My research describes the connection between physical properties of modern quantum materials and the nature of quantum entanglement in the many-particle wavefunction. I have made contributions to the description of the diverse varieties of entangled states of quantum matter. These include states with topological order, with and without an energy gap to excitations, and critical states without quasiparticle excitations. Many of these contributions have been linked to experiments, especially to the rich phase diagrams of the high temperature superconductors.

Extreme examples of complex quantum entanglement arise in metallic states of matter without quasiparticle excitations, often called strange metals. Remarkably, there is an intimate connection between the quantum physics of strange metals found in modern materials (which can be studied in tabletop experiments), and quantum entanglement near black holes of astrophysics. I have exploited this connection to advance our understanding of experiments on strange metals

Positions Held

  • Herchel Smith Professor of Physics at Harvard University, July 1, 2015 onwards
  • Professor of Physics at Harvard University, July 1, 2005 to June 30, 2015
  • Professor of Physics and Applied Physics at Yale University, July 1, 1995 to June 30, 2005
  • Associate Professor (tenured) of Physics and Applied Physics at Yale University, July 1, 1992 to June 30, 1995
  • Associate Professor (term) of Physics and Applied Physics at Yale University, July 1, 1989 to June 30, 1992
  • Assistant Professor of Physics and Applied Physics at Yale University, July 1, 1987 to June 30, 1989
  • Postdoctoral Member of Technical Staff at AT&T Bell Laboratories, Murray Hill, NJ from September 1, 1985 to August 31, 1987.

Awards

  • Lars Onsager Prize, American Physical Society, 2018. Citation: for his seminal contributions to the theory of quantum phase transitions, quantum magnetism, and fractionalized spin liquids, and for his leadership in the physics community.
  • Dirac Medal for the Advancement of Theoretical Physics, awarded by the Australian Institute of Physics, the University of New South Wales, and the Royal Society of New South Wales, 2015, from an endowment set up by Dirac. Citation: The Dirac Medal was awarded to Professor Sachdev in recognition of his many seminal contributions to the theory of strongly interacting condensed matter systems: quantum phase transitions, including the idea of critical deconfinement and the breakdown of the conventional symmetry based Landau-Ginsburg-Wilson paradigm; the prediction of exotic 'spin-liquid' and fractionalized states; and applications to the theory of high-temperature superconductivity in the cuprate materials.
  • Elected to the U.S. National Academy of Sciences, April 2014. Citation: Sachdev has made seminal advances in the theory of condensed matter systems near a quantum phase transition, which have elucidated the rich variety of static and dynamic behavior in such systems, both at finite temperatures and at T = 0. His book, Quantum Phase Transitions, is the basic text of the field.

Recent Publications

  • Thermal and electrical transport in metals and superconductors across antiferromagnetic and topological quantum transitions, S. Chatterjee, A. Eberlein, and S. Sachdev, Physical Review B 96, 075103 (2017); arXiv: 1704.02329
  • Quantum butterfly effect in weakly interacting diffusive metals, A. A. Patel, D. Chowdhury, S. Sachdev, and B. Swingle, Physical Review X 7, 031047 (2017); arXiv: 1703.07353
  • Insulators and metals with topological order and discrete symmetry breaking, S. Chatterjee and S. Sachdev, Physical Review B 95, 205133 (2017); arXiv: 1703.00014
  • Quantum electrodynamics in 2+1 dimensions with quenched disorder: quantum critical states with interactions and disorder, A. Thomson and S. Sachdev, Physical Review B 95, 235146 (2017); arXiv: 1702.04723
  • Spectrum of the Wilson-Fisher conformal field theory on the torus, S. Whitsitt, M. Schuler, L.-P. Henry, A. M. Läuchli, and S. Sachdev, Physical Review B 96, 035142 (2017); arXiv: 1701.03111
  • Thermoelectric transport in disordered metals without quasiparticles: the Sachdev-Ye-Kitaev models and holography, R. A. Davison, Wenbo Fu, Yingfei Gu, A. Georges, K. Jensen, and S. Sachdev, Physical Review B 95, 155131 (2017); arXiv: 1612.00849
  • Quantum chaos on a critical Fermi surface, A. A. Patel and S. Sachdev, Proceedings of the National Academy of Sciences 114, 1844 (2017); arXiv: 1611.00003
  • Supersymmetric Sachdev-Ye-Kitaev models, Wenbo Fu, D. Gaiotto, J. Maldacena, and S. Sachdev, Physical Review D 95, 026009 (2017); arXiv: 1610.08917
  • Entanglement entropy of the large N Wilson-Fisher conformal field theory, S. Whitsitt, W. Witczak-Krempa, and S. Sachdev, Physical Review B 95, 045148 (2017); arXiv: 1610.06568
  • Holography of the Dirac Fluid in graphene with two currents, Yunseok Seo, Geunho Song, Philip Kim, S. Sachdev, and Sang-Jin Sin, Physical Review Letters 118, 036601 (2017); arXiv: 1609.03582.
  • A fractionalized Fermi liquid with bosonic chargons as a candidate for the pseudogap metal, S. Chatterjee and S. Sachdev, Physical Review B 94, 205117 (2016); arXiv: 1607.05727
  • Shear viscosity at the Ising-nematic quantum critical point in two dimensional metals, A. A. Patel, A. Eberlein, and S. Sachdev, Physical Review B 95, 075127 (2017); arXiv: 1607.03894
  • Spectrum of conformal gauge theories on a torus, A. Thomson and S. Sachdev, Physical Review B 95, 205128 (2017); arXiv: 1607.05279
  • Fermi surface reconstruction and drop of Hall number due to spiral antiferromagnetism in high-Tc cuprates, A. Eberlein, W. Metzner, S. Sachdev, and H. Yamase, Physical Review Letters 117, 187001 (2016); arXiv: 1607.06087
  • Spin density wave order, topological order, and Fermi surface reconstruction, S. Sachdev, E. Berg, S. Chatterjee, and Y. Schattner, Physical Review B 94, 115147 (2016); arXiv: 1606.07813
  • Electronic quasiparticles in the quantum dimer model: density matrix renormalization group results, Junhyun Lee, S. Sachdev, and S. R. White, Physical Review B 94, 115112 (2016); arXiv: 1606.04105
  • Hyperscaling violation at the Ising-nematic quantum critical point in two dimensional metals, A. Eberlein, I. Mandal, and S. Sachdev, Physical Review B 94, 045133 (2016); arXiv: 1605.00657
  • Hydrodynamic theory of thermoelectric transport and negative magnetoresistance in Weyl semimetals, A. Lucas, R. Davison, and S. Sachdev, Proceedings of the National Academy of Sciences 113, 9463 (2016); arXiv: 1604.08598
  • Superconductivity from a confinement transition out of a FL* metal with Z2 topological and Ising-nematic orders, S. Chatterjee, Y. Qi, S. Sachdev, and J. Steinberg, Physical Review B 94, 024502 (2016); arXiv: 1603.03041
  • Numerical study of fermion and boson models with infinite-range random interactions, Wenbo Fu and S. Sachdev, Physical Review B 94, 035135 (2016); arXiv: 1603.05246
  • Transition from the Z2 spin liquid to antiferromagnetic order: spectrum on the torus, S. Whitsitt and S. Sachdev, Physical Review B 94, 085134 (2016); arXiv: 1603.05652
  • Confinement transition to density wave order in metallic doped spin liquids, A. A. Patel, D. Chowdhury, A. Allais, and S. Sachdev, Physical Review B 93, 165139 (2016); arXiv: 1602.05954
  • Emergent gauge fields and the high temperature superconductors, S. Sachdev, Philosophical Transactions of the Royal Society A 374, 20150248 (2016); arXiv: 1512.00465
  • Fractionalized Fermi liquid on the surface of a topological Kondo insulator, A. Thomson and S. Sachdev, Physical Review B 93, 125103 (2016); arXiv: 1509.03314
  • Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene, J. Crossno, Jing K. Shi, Ke Wang, Xiaomeng Liu, A. Harzheim, A. Lucas, S. Sachdev, Philip Kim, Takashi Taniguchi, Kenji Watanabe, T. A. Ohki, and Kin Chung Fong, Science 351, 1058 (2016); arXiv: 1509.04713
  • Transport in inhomogeneous quantum critical fluids and in the Dirac fluid in graphene, A. Lucas, J. Crossno, Kin Chung Fong, Philip Kim, and S. Sachdev, Physical Review B 93, 075426 (2016); arXiv: 1510.01738
  • Atomic-scale Electronic Structure of the Cuprate d-Symmetry Form Factor Density Wave State, M. H. Hamidian, S. D. Edkins, Chung Koo Kim, J. C. Davis, A. P. Mackenzie, H. Eisaki, S. Uchida, M. J. Lawler, E.-A. Kim, S. Sachdev, and K. Fujita, Nature Physics 12, 150 (2016); arXiv: 1507.07865
  • Fermionic spinon theory of square lattice spin liquids near the Néel state, A. Thomson and S. Sachdev, arXiv: 1708.04626
  • Quantum quench of the Sachdev-Ye-Kitaev model, A. Eberlein, V. Kasper, S. Sachdev, and J. Steinberg, arXiv: 1706.07803
  • Intertwining topological order and broken symmetry in a theory of fluctuating spin density waves, S. Chatterjee, S. Sachdev, and M. S. Scheurer, arXiv: 1705.06289
  • Thermal diffusivity and chaos in metals without quasiparticles, M. Blake, R. A. Davison, and S. Sachdev, arXiv: 1705.07896
  • Magnetic-field Induced Interconversion of Cooper Pairs and Density Wave States within Cuprate Composite Order, M. H. Hamidian, S. D. Edkins, K. Fujita, A. Kostin, A. P. Mackenzie, H. Eisaki, S. Uchida, M. J. Lawler, E.-A. Kim, S. Sachdev, and J. C. Davis, arXiv: 1508.00620
  • Holographic quantum matter, S. A. Hartnoll, A. Lucas, and S. Sachdev, to be published by MIT press, arXiv: 1612.07324

Seminars

  • New Horizons in Quantum Matter (Physics Next: From Quantum Fields to Condensed Matter, Riverhead, NY Aug 24-26, 2017)
  • Quantum matter without quasiparticles (Electron-electron Interactions in Topological Materials, Center for Advanced 2D Materials, National University of Singapore, June 28-30, 2017)
  • Equilibrium and non-equilibrium dynamics of SYK models (Strongly Interacting Conformal Field Theory in Condensed Matter Physics, Institute for Advanced Study, Tsinghua University, Beijing, June 25, 2017)
  • Z2 topological order near the Neel state on the square lattice (University of Heidelberg, April 28, 2017)
  • Quantum entanglement, strange metals, and black holes (University of Würzburg, April 27, 2017)
  • Quantum entanglement, strange metals, and black holes (University of Washington, Seattle, April 10, 2017)
  • Quantum entanglement, strange metals, and black holes (University of Heidelberg, April 27, 2017)
  • Quantum entanglement, strange metals, and black holes (Duke University, April 5, 2017)
  • From the pseudogap to the strange metal (Common Threads in the Electronic Phase Diagram of Unconventional Superconductors, Lorentz Institute, Leiden, March 2, 2017)
  • From the pseudogap to the strange metal (APS March meeting, New Orleans, March 13, 2017)
  • Quantum entanglement, strange metals, and black holes (Washington University, St. Louis, March 22, 2017)
  • Quantum entanglement, strange metals, and black holes (University of Montreal, March 24, 2017)
  • Quantum entanglement, strange metals, and black holes (Public Lecture, Simons Foundation, New York, February 8, 2017)
  • Disordered metals without quasiparticles, and charged black holes (String Theory: Past and Present (SpentaFest), International Center for Theoretical Sciences, Bengaluru January 11, 2017)
  • Lectures at the 34th Jerusalem Winter School in Theoretical Physics, New Horizons in Quantum Matter, December 27, 2016 - January 5, 2017
  • Lectures at the Tata Institute of Fundamental Research, Mumbai, January 11-19, 2017
  • Quantum entanglement, strange metals, and black holes (13th Homi Bhabha Public Lecture, Tata Institute of Fundamental Research, Mumbai, January 17, 2017)
  • Quantum matter without quasiparticles: SYK models, strange metals, and black holes (University of Maryland, College Park, December 13, 2016)
  • Topology and the phases of quantum matter in two dimensions (2016 Nobel prize in physics, impact on physics research and future directions, Stockholm University, December 8, 2016)
  • SYK models, strange metals, and black holes (University of Illinois, Urbana, December 5, 2016)
  • Quantum matter without quasiparticles: SYK models, black holes, and the cuprate strange metal (Workshop on Frontiers of Quantum Materials, Rice University, Houston, November 4, 2016)
  • The SYK model of non-Fermi liquids and black holes (Applications of Gauge-Gravity Duality 2016, Chalmers University of Technology, Gothenburg, Sweden, October 4, 2016)
  • Strange metals, black holes, and graphene (Physics Colloquium, Chalmers University of Technology, Gothenburg, Sweden, October 4, 2016)
  • The SYK models of non-Fermi liquids and black holes (QMATH13: Mathematical Results in Quantum Physics, Georgia Tech, Atlanta, October 9, 2016)
  • Strange metals, black holes, and graphene (Workshop on Chaos, the SYK Model and AdS2, Institute for Advanced Study, Princeton, October 17-19, 2016)
  • SYK models and black holes (Black Hole Initiative Colloquium, Harvard University, October 25, 2016)
  • Theories of non-Fermi liquids (Quantum Criticality and Topology in Itinerant Electron Systems, Center for Non-linear Studies, Albuquerque August 18, 2016)
  • Quantum matter without quasiparticles: random fermion models, black holes, graphene, and non-Fermi liquids (Workshop on Non-equilibrium Physics and Holography, St. John's College, Oxford, July 13, 2016)
  • Quantum matter without quasiparticles: random fermion models, black holes, and graphene (Quantum Matter, Spacetime, and Information, Yukawa International Seminar, Yukawa Institute for Theoretical Physics, Kyoto, June 15, 2016)
  • Quantum matter without quasiparticles: graphene, random fermion models, and black holes (Discussion Meeting on Current Frontiers in Condensed Matter Research, International Centre for Theoretical Sciences, Bengaluru, June 27, 2016)
  • Entangled phases of quantum matter (3 lectures at the School on Current Frontiers in Condensed Matter Research, International Centre for Theoretical Sciences, Bengaluru, June 23-26, 2016)
  • Quantum matter without quasiparticles: random fermion models, black holes, and graphene (Interacting Electrons and Quantum Magnetism, Technion, Haifa, June 20, 2016)
  • Quantum matter without quasiparticles (Max Planck Institute for Complex Systems, Dresden, May 22, 2016)
  • Quantum entanglement and the phases of matter (University of North Carolina, Chapel Hill, April 18, 2016)
  • Quantum entanglement and the phases of matter (PRL Conference on Condensed Matter Physics, Physical Research Laboratory, Ahmedabad, April 13, 2016)
  • The novel metallic states of the cuprates: "topological" Fermi liquids (FL*) and strange metals (PRL Conference on Condensed Matter Physics, Physical Research Laboratory, Ahmedabad, April 11, 2016)
  • Emergent gauge fields and high temperature superconductivity (Nambu Memorial Symposium, University of Chicago, March 12, 2016)
  • The pseudogap metal and FL* (a "topological" Fermi liquid) (American Physical Society meeting, Baltimore, March 14, 2016)
  • Antiferromagnetism, high temperature superconductivity, and quantum criticality (New York University, March 6, 2016)
  • Antiferromagnetism and high temperature superconductivity (Basic Research Needs Workshop on Quantum Materials for Energy Relevant Technology, Department of Energy, Gaithersburg MD, February 8, 2016)
  • Compressible quantum matter: connecting field theories and holography (Gauge/Gravity Duality and Condensed Matter Physics, Banff International Research Station, Banff, Canada, February 29, 2016)
  • Quantum matter without quasiparticles (University of Chicago, February 18, 2016)
  • Quantum-critical fluid in graphene (ARO MURI meeting, Berkeley, January 11, 2016)
  • Confinement transition out of a FL* metal with Z2 topological and Ising-nematic order (Intertwined Order in Strongly Correlated Systems, Laguna Beach, CA, January 29-31, 2016)
  • Emergent "light" and the high temperature superconductors (Pennsylvania State University, State College, Jan 21, 2016)
  • Quantum phases of graphene (Emergent Phenomena in Quantum Hall Systems, Tata Institute for Fundamental Research, Mumbai, January 9, 2016)
  • Strange metals and black holes (Tata Institute for Fundamental Research, Mumbai, January 5, 2016)
  • Exotic metals in graphene and the high temperature superconductors (New questions in quantum field theory from condensed matter theory, International Center for Theoretical Sciences, Bengaluru, December 28, 2015)
  • Emergent gauge fields and the high temperature superconductors (Unifying physics and technology in light of Maxwell's equations, The Royal Society, London, November 16, 2015)
  • Long-range quantum entanglement in metals (Albanova and Nordita Colloquium, Stockholm, November 12, 2015)
  • Dynamics and Transport in Strange Metals (Centre de Recherches Mathematiques, University of Montreal, October 21, 2015)
  • Dynamics and Transport in Strange Metals (Stanford University, October 16, 2015)
  • Quantum Entanglement and Superconductivity (Cenovus Energy, Calgary, October 23, 2015)
  • Bekenstein-Hawking entropy and strange metals (CMSA Colloquium, Harvard, September 16, 2015)
  • Strange metals and black holes (Rutgers University, September 9, 2015)
  • Strange metals and black holes (Boston University, September 29, 2015)
  • Quantum Entanglement and Superconductivity (Dirac Lecture, University of New South Wales, Sydney, Australia, September 1, 2015)
  • The two unusual metals in the cuprates (Moore Foundation EPIQS Symposium, Sausalito, August 6, 2015)
  • Metals with long-range entanglement (University of New South Wales, Sydney, Australia, August 31, 2015)
  • The metallic states of the cuprates (School on Strongly Coupled Field Theories for Condensed Matter and Quantum Information Theory, International Institute of Physics, Natal, Brazil, August 13-14, 2015)
  • The "normal" states of the cuprates (Summer School on Emergent Phenomena in Quantum Materials, Cornell University, August 4, 2015)