Biomedical subjects

Igor F Herbut

Publications and source records attributed to Igor F Herbut.

5 recordsLinked to original sources

PubMed2006

Interactions and phase transitions on graphene's honeycomb lattice.

The low-energy theory of interacting electrons on graphene's two-dimensional honeycomb lattice is derived and discussed. In particular, the Hubbard model in the large-N limit is shown to have a semimetal-antiferromagnetic insulator quantum critical point in the universality class of the Gross-Neveu model. The same equivalence is conjectured to hold in the physical case N=2, and its consequences for various physical quantities are examined. The effects of the long-range Coulomb interaction and the magnetic field are discussed.

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PubMed2006

Stable Skyrmions in spinor condensates.

Globally symmetric spinor condensates in free space are argued not to support stable topological defects in either two or three dimensions. In the latter case, however, we show that a topological Skyrmion can be stabilized by forcing it to adopt certain density profiles. A sufficient condition for the existence of Skyrmion solutions in three dimensions is formulated and illustrated in simple examples. Our results pertain to Bose-Einstein condensation in 87Rb.

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PubMed2005

Effective theory of high-temperature superconductors.

The field theory of a fluctuating d-wave superconductor is constructed and proposed as an effective description of superconducting cuprates at low energies. The theory is used to resolve a puzzle posed by recent experiments on superfluid density in severely underdoped YBa2(Cu3)O(6+x). In particular, the overall temperature dependence of the superfluid density at low dopings is argued to be described well by the strongly anisotropic weakly interacting Bose gas, and thus approximately linear in temperature with an almost doping-independent slope.

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PubMed2003

Permanent confinement in the compact QED3 with fermionic matter.

We argue that the compact three dimensional electrodynamics with massless relativistic fermions is always in the confined phase, in spite of the bare interaction between the magnetic monopoles being rendered logarithmic by fermions. The effect is caused by screening by other dipoles, which transforms the logarithmic back into the Coulomb interaction at large distances. Possible implications for the chiral symmetry breaking for fermions are discussed, and the global phase diagram of the theory is proposed.

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PubMed2002

Antiferromagnetism from phase disordering of a d-wave superconductor.

The unbinding of vortex defects in the superconducting condensate with d-wave symmetry at T = 0 is shown to lead to the insulator with incommensurate spin-density-wave order. The transition is similar to the spontaneous generation of the chiral mass in the three-dimensional quantum electrodynamics. A possible relation to recent experiments on underdoped cuprates is discussed.

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