Tensor renormalization group approach to four-dimensional complex $\phi^4$ theory at finite density

Understand

Tensor network is an attractive approach to field theory with negative sign problem.

• The complex $\phi^4$ theory at finite density is a test bed for numerical algorithms to verify their effectiveness.
• The model shows a characteristic feature called the Silver Blaze phenomenon associated with the sign problem in the large volume limit at low temperature.
• We analyze the four-dimensional model employing the anisotropic tensor renormalization group algorithm.