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arXiv · 2208.04623

U(1)-symmetric Gaussian fermionic projected entangled paired states and their Gutzwiller projection

Jheng-Wei Li·Jan von Delft·Hong-Hao Tu
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Abstract

We develop a formalism for constructing particle-number-conserving Gaussian fermionic projected entangled pair states [U(1)-GfPEPS] and show that these states can describe ground states of band insulators and gapless fermions with band touching points. When using them as variational Ans\"{a}tze for two Dirac fermion systems ($\pi$-flux model on the square lattice and $[0,\pi]$-flux model on the kagome lattice), we find that the U(1)-GfPEPS, even with a relatively small bond dimension, can accurately approximate the Dirac Fermi sea ground states. By applying Gutzwiller projectors on top of these U(1)-GfPEPS, we obtain PEPS representation of U(1)-Dirac spin liquid states for spin-1/2 systems. With state-of-the-art tensor network numerics, the critical exponent in the spin-spin correlation function of the Gutzwiller-projected $\pi$-flux state is estimated to be $\eta \approx 1.7$.

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Jheng-Wei Li, Jan von Delft, Hong-Hao Tu. 2022-08-09. U(1)-symmetric Gaussian fermionic projected entangled paired states and their Gutzwiller projection. https://doi.org/10.1103/physrevb.107.085148

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