A short proof of the Quantum Substate Theorem

8 years 8 days ago
A short proof of the Quantum Substate Theorem
The Quantum Substate Theorem due to Jain, Radhakrishnan, and Sen [7] gives us a powerful operational interpretation of the observational divergence of two quantum states, a quantity that is closely related to their relative entropy. Informally, the theorem states that if the observational divergence between two quantum states ρ, σ is small, then there is a quantum state ρ close to ρ in trace distance, such that ρ when scaled down by a small factor becomes a substate of σ. We present a new proof of this theorem. The resulting statement is stronger and its proof is both conceptually simpler and significantly shorter than the earlier proof.
Rahul Jain, Ashwin Nayak
Added 13 May 2011
Updated 13 May 2011
Type Journal
Year 2011
Where CORR
Authors Rahul Jain, Ashwin Nayak
Comments (0)