918 research outputs found
Exact Strongly Coupled Fixed Point in Theory
We show explicitly how a strongly coupled fixed point can be constructed in
scalar theory from the solutions to a non-linear eigenvalue
problem. The fixed point exists only for , is unstable and characterized
by (correlation length exponent), (anomalous
dimension). For , these exponents reproduce to those of the Ising model
which can be understood from the codimension of the critical point. At this
fixed point, terms with are all irrelevant. The testable
prediction of this fixed point is that the specific heat exponent vanishes. 2d
critical Mott systems are well described by this new fixed point.Comment: revised version of previous paper with a proof of the irrelevance of
\varphi^6 and higher terms at fixed poin
Orbital Resonance Mode in Superconducting Iron Pnictides
We show that the fluctuations associated with ferro orbital order in the
and orbitals can develop a sharp resonance mode in the
superconducting state with a nodeless gap on the Fermi surface. This orbital
resonance mode appears below the particle-hole continuum and is analogous to
the magnetic resonance mode found in various unconventional superconductors. If
the pairing symmetry is , a dynamical coupling between the orbital
ordering and the d-wave subdominant pairing channels is present by symmetry.
Therefore the nature of the resonance mode depends on the relative strengths of
the fluctuations in these two channels, which could vary significantly for
different families of the iron based superconductors. The application of our
theory to a recent observation of a new -function-like peak in the
B Raman spectrum of BaKFeAs is discussed.Comment: 6 pages, 3 figure
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