Positive Hamiltonians can give purely exponential decay

Abstract

It is commonly claimed that only Hamiltonians with a spectrum unbounded both above and below can give purely exponential decay. Because such Hamiltonians have no ground state, they are considered unphysical. Here we show that Hamiltonians which are bounded below can give purely exponential decay. This is possible when, instead of looking at the global survival probability, one considers a subsystem only. We conclude that purely exponential decay might not be as unphysical as previously thought.

4 pages

Cited by in corpus (8)

• Nonexponential quantum decay under environmental decoherence
• Experimental investigation of quantum decay at short, intermediate and long times via integrated photonics
• Quantum regression in dephasing phenomena
• Decoherence factor as a convolution: an interplay between a Gaussian and an exponential coherence loss
• Nonexponential decay of Feshbach molecules
• Decoherence dynamics in molecular qubits: Exponential, Gaussian and beyond
• Quantum-Dynamical Semigroups and the Church of the Larger Hilbert Space
• Positive Hamiltonians cannot give exponential decay of positive observables