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T Senthil

Publications and source records attributed to T Senthil.

12 recordsLinked to original sources
PubMed2006

Emergence of artificial photons in an optical lattice.

We establish the theoretical feasibility of direct analog simulation of the compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We discuss the realizability of the topological Coulomb phase in extended Bose-Hubbard models in several optical lattice geometries. We predict the testable signatures of this emergent phase in noise correlation measurements, thus suggesting the possible emergence of artificial light in optical lattices.

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PubMed2006

Spin nematics and magnetization plateau transition in anisotropic kagome magnets.

We study S=1 kagome antiferromagnets with an isotropic Heisenberg exchange J and strong easy-axis single-ion anisotropy D. For D>>J, the low-energy physics can be described by an effective S=1/2 XXZ model with antiferromagnetic Jz approximately J and ferromagnetic J perpendicular approximately J2/D. Exploiting this connection, we argue that nontrivial ordering into a "spin-nematic" occurs whenever D dominates over J, and discuss its experimental signatures. We also study a magnetic field induced transition to a magnetization plateau state at magnetization 1/3 which breaks lattice translation symmetry due to ordering of the Sz and occupies a lobe in the B/Jz-Jz/J perpendicular phase diagram.

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PubMed2006

Fractionalization, topological order, and quasiparticle statistics.

We argue, based on general principles, that topological order is essential to realize fractionalization in gapped insulating phases in dimensions d > or = 2. In d = 2 with genus g, we derive the existence of the minimum topological degeneracy q(g) if the charge is fractionalized in units of 1/q, irrespective of microscopic model or effective theory. Furthermore, if the quasiparticle is either boson or fermion, it must be at least q(2g).

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PubMed2005

Vortices and quasiparticles near the superconductor-insulator transition in thin films.

We study the low temperature behavior of an amorphous superconducting film driven normal by a perpendicular magnetic-field (B). For this purpose we introduce a new two-fluid formulation consisting of fermionized field-induced vortices and electrically neutralized Bogoliubov quasiparticles (spinons) interacting via a long-ranged statistical interaction. This approach allows us to access a novel non-Fermi-liquid phase, which naturally interpolates between the low B superconductor and the high B normal metal. We discuss the properties of the resulting "vortex metal" phase.

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PubMed2004

Deconfined quantum critical points.

The theory of second-order phase transitions is one of the foundations of modern statistical mechanics and condensed-matter theory. A central concept is the observable order parameter, whose nonzero average value characterizes one or more phases. At large distances and long times, fluctuations of the order parameter(s) are described by a continuum field theory, and these dominate the physics near such phase transitions. We show that near second-order quantum phase transitions, subtle quantum interference effects can invalidate this paradigm, and we present a theory of quantum critical points in a variety of experimentally relevant two-dimensional antiferromagnets. The critical points separate phases characterized by conventional "confining" order parameters. Nevertheless, the critical theory contains an emergent gauge field and "deconfined" degrees of freedom associated with fractionalization of the order parameters. We propose that this paradigm for quantum criticality may be the key to resolving a number of experimental puzzles in correlated electron systems and offer a new perspective on the properties of complex materials.

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PubMed2003

Fractionalized fermi liquids.

In spatial dimensions d>or=2, Kondo lattice models of conduction and local moment electrons can exhibit a fractionalized, nonmagnetic state (FL(*)) with a Fermi surface of sharp electronlike quasiparticles, enclosing a volume quantized by (rho(a)-1)(mod 2), with rho(a) the mean number of all electrons per unit cell of the ground state. Such states have fractionalized excitations linked to the deconfined phase of a gauge theory. Confinement leads to a conventional Fermi liquid state, with a Fermi volume quantized by rho(a)(mod 2), and an intermediate superconducting state for the Z2 gauge case. The FL(*) state permits a second order metamagnetic transition in an applied magnetic field.

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PubMed2002

Exotic order in simple models of bosonic systems.

We show that simple Bose Hubbard models with unfrustrated hopping and short range two-body repulsive interactions can support stable fractionalized phases in two and higher dimensions, and in zero magnetic field. The simplicity of the constructed models advances the possibility of a controlled experimental realization and novel applications of such unconventional states.

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PubMed2001

Fractionalization in the cuprates: detecting the topological order.

The precise theoretical characterization of a fractionalized phase in spatial dimensions higher than one is through the concept of "topological order." We describe a physical effect that is a robust and a direct consequence of this hidden order that should enable a precise experimental characterization of fractionalized phases. In particular, we propose specific "smoking-gun" experiments to unambiguously settle the issue of electron fractionalization in the underdoped cuprates.

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