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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

  • 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

  • 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
  • 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
  • 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
  • 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
  • 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, arXiv: 1607.06087
  • A fractionalized Fermi liquid with bosonic chargons as a candidate for the pseudogap metal, S. Chatterjee and S. Sachdev, arXiv: 1607.05727
  • Spectrum of conformal gauge theories on a torus, A. Thomson and S. Sachdev, arXiv: 1607.05279
  • Shear viscosity at the Ising-nematic quantum critical point in two dimensional metals, A. A. Patel, A. Aberlein, and S. Sachdev, arXiv: 1607.03894.
  • Spin density wave order, topological order, and Fermi surface reconstruction, S. Sachdev, E. Berg, S. Chatterjee, and Y. Schattner, arXiv: 1606.07813
  • The novel metallic states of the cuprates: topological Fermi liquids and strange metals, S. Sachdev and D. Chowdhury, arXiv: 1605.03579
  • Universal Signatures of Quantum Critical Points from Finite-Size Torus Spectra: A Window into the Operator Content of Higher-Dimensional Conformal Field Theories, M. Schuler, S. Whitsitt, L.-P. Henry, S. Sachdev, and A. M. Läuchli, arXiv: 1603.03042
  • 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

Seminars

  • 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)
  • 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: 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)
  • 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: 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 (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)
  • The pseudogap metal and FL* (a "topological" Fermi liquid) (American Physical Society meeting, Baltimore, March 14, 2016)
  • Emergent gauge fields and high temperature superconductivity (Nambu Memorial Symposium, University of Chicago, March 12, 2016)
  • Antiferromagnetism, high temperature superconductivity, and quantum criticality (New York University, March 6, 2016)
  • Quantum matter without quasiparticles (University of Chicago, February 18, 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)
  • Antiferromagnetism and high temperature superconductivity (Basic Research Needs Workshop on Quantum Materials for Energy Relevant Technology, Department of Energy, Gaithersburg MD, February 8, 2016)
  • Quantum phases of graphene (Emergent Phenomena in Quantum Hall Systems, Tata Institute for Fundamental Research, Mumbai, January 9, 2016)
  • Quantum-critical fluid in graphene (ARO MURI meeting, Berkeley, January 11, 2016)
  • Emergent "light" and the high temperature superconductors (Pennsylvania State University, State College, Jan 21, 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)
  • 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)
  • Long-range quantum entanglement in metals (Albanova and Nordita Colloquium, Stockholm, November 12, 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)
  • Quantum Entanglement and Superconductivity (Cenovus Energy, Calgary, October 23, 2015)
  • Dynamics and Transport in Strange Metals (Stanford University, October 16, 2015)
  • Dynamics and Transport in Strange Metals (Centre de Recherches Mathematiques, University of Montreal, October 21, 2015)
  • Quantum Entanglement and Superconductivity (Dirac Lecture, University of New South Wales, Sydney, Australia, September 1, 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)
  • The "normal" states of the cuprates (Summer School on Emergent Phenomena in Quantum Materials, Cornell University, August 4, 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 two unusual metals in the cuprates (Moore Foundation EPIQS Symposium, Sausalito, August 6, 2015)