2,503 research outputs found
Modular matrices from universal wave function overlaps in Gutzwiller-projected parton wave functions
We implement the universal wave function overlap (UWFO) method to extract
modular and matrices for topological orders in Gutzwiller-projected
parton wave functions (GPWFs). The modular and matrices generate a
projective representation of on the degenerate-ground-state
Hilbert space on a torus and may fully characterize the 2+1D topological
orders, i.e. the quasi-particle statistics and chiral central charge (up to
bosonic quantum Hall states). We used the variational Monte Carlo method
to computed the and matrices of the chiral spin liquid (CSL)
constructed by the GPWF on the square lattice, and confirm that the CSL carries
the same topological order as the bosonic Laughlin state. We
find that the non-universal exponents in UWFO can be small and direct numerical
computation is able to be applied on relatively large systems. We also discuss
the UWFO method for GPWFs on other Bravais lattices in two and three dimensions
by using the Monte Carlo method. UWFO may be a powerful method to calculate the
topological order in GPWFs.Comment: 5 pages with 3 figure
Quantum Oscillation as Diagnostics of Pseudogap State in Underdoped Cuprates
The Fermi surface in underdoped cuprates is reconstructed by the charge
density wave (CDW) order in the pseudogap phase. Theoretical proposals can be
divided into two classes: one assumes the underlying Fermi surface without CDW
as a conventional large surface; the other assumes small hole-like Fermi
pockets. In both scenarios, we theoretically study the quantum oscillation and
find three evenly spaced peaks in the oscillation spectra. The central dominant
peak is induced by the CDW order. Its effective mass is strongly enhanced as
the CDW vanishes in agreement with experiments. But the two scenarios have
different understandings of the subdominant satellite peaks. In the
large-surface scenario they are induced by the interlayer tunneling between the
bilayer CuO planes. Their effective masses are also enhanced with
descreasing CDW. In the small-pocket scenario one of the subdominant peaks
comes from the original small Fermi pockets of the pseudogap state. Its
effective mass is nearly independent of the CDW strength and increases
monotonically with the doping. We propose future quantum oscillation
experiments to test these different predictions and thus to clarify the
underlying Fermi surface structure of the pseudogap state.Comment: published versio
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