Exact NMR simulation of protein-size spin systems using tensor train formalism

Understand

We introduce a new method, based on alternating optimization, for compact representation of spin Hamiltonians and solution of linear systems of algebraic equations in the tensor train format.

• We demonstrate the method's utility by simulating, without approximations, a 15N NMR spectrum of ubiquitin --- a protein containing several hundred interacting nuclear spins.
• Existing simulation algorithms for the spin system and the NMR experiment in question either require significant approximations or scale exponentially with the spin system size.
• We compare the proposed method to the Spinach package that uses heuristic restricted state space techniques to achieve polynomial complexity scaling.