Localized Excitations from Localized Unitary Operators

Understand

Localized unitary operators are basic probes of locality and causality in quantum systems: localized unitary operators create localized excitations in entangled states.

• Working with an explicit form, we explore the properties of these operators in quantum mechanics and quantum field theory.
• We show that, unlike unitary operators, local non-unitary operators generically create non-local excitations.
• We present a local picture for quantum systems in which localized experimentalists can only act through localized Hamiltonian deformations, and therefore localized unitary operators.