Looking for hard quantum problems? Follow the entangled sign 😉
If a quantum wave function is not allowed to have positive and negative parts, then a quantum computer is only as powerful as a classical computer. On the other hand, without complex numbers, quantum computers are still powerful. This may imply that a quantum problem without signs can be simulated on a classical computer.
A state that is not too entangled can also be simulated on a classical computer. This could be the motivation behind tensor network and DMRG.
- Lattice Methods:
- Core Concepts:
- Continuum Methods
- Variational Monte Carlo (VMC)
- Diffusion Monte Carlo (DMC)
- Path Integral Monte Carlo (PIMC)