695 research outputs found
Berezinskii-Kosterlitz-Thouless transition in lattice Schwinger model with one flavor of Wilson fermion
We have made a detailed study of the phase structure for the lattice Schwinger model with one flavor of Wilson fermion on the (m,g) plane. For numerical investigation, we develop a decorated tensor renormalization method for lattice gauge theories with fermions incorporating the Grassmann tensor renormalization. Our algorithm manifestly preserves rotation and reflection symmetries. We find not only a parity-broken phase but also a Berezinskii-Kosterlitz-Thouless (BKT) transition by evaluating the central charge and an expectation value of a projection operator into the parity-odd subspace. The BKT phase boundaries converge into the degenerated doubler pole (m,g)=(−2,0), while the parity-breaking transition line ends at the physical pole (m,g)=(0,0). In addition, our analysis of scaling dimensions indicates that a conformal field theory with SU(2) symmetry arises on the line of m=−2
Grassmann tensor renormalization group approach to one-flavor lattice Schwinger model
We apply the Grassmann tensor renormalization group to the lattice regularized Schwinger model with one-flavor of the Wilson fermion. We study the phase diagram in the (β,κ) plane performing a detailed analysis of the scaling behavior of the Lee-Yang zeros and the peak height of the chiral susceptibility. Our results strongly indicate that the whole range of the phase transition line starting from (β,κ)=(0.0,0.380665(59)) and ending at (∞,0.25) belongs to the two-dimensional Ising universality class similar to the free fermion case
Microscopic mechanism of structural and volume relaxation below glass transition temperature in a soda-lime silicate glass revealed by Raman spectroscopy and its first principle calculations
To elucidate the atomistic origin of volume relaxation in soda-lime silicate
glass annealed below the glass transition temperature (Tg), the experimental
and calculated Raman spectra were compared. By decomposing the calculated Raman
spectra into a specific group of atoms, we found that the Raman peak at 1050
cm-1 corresponds to bridging oxygen with a small Si-O-Si bond angle. The
experimental Raman spectra indicated that, during annealing below Tg, a
homogenization reaction Q2+Q4->2Q3 proceeds in the early stage of structural
relaxation. Then, the Si-O-Si units with relatively small angles decrease even
in the later stages, which is first evidence of ring deformation causing volume
relaxation of soda-lime silicate glass because decreasing small Si-O-Si angles
corresponds to the reduce of acute O-O-O angle in a ring and can expand the
space inside the rings, and Na can be inserted into the ring center. In
conclusion the ring deformation and Na displacement is the origin of the volume
relaxation of soda-lime silicate glass below Tg.Comment: 15 figures and 1 table for main text, 8 figures and 1 table for
supplemental inf
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