Entanglement entropy is one of the most important measures of quantum entanglement. Can entanglement entropy be measured in experiments? Is entanglement entropy related to some experimentally accessible observables? Here I will discuss a mathematical relation between quantum noise and entanglement entropy, known as the Klich-Levitov formula [1]. After a brief introduction to entanglement entropy and full counting statistics [2], I will prove the Klich-Levitov formula following Ref. [1]. I will then apply the Klich-Levitov formula to a simple quantum tunneling process and compute the entropy production in such a process.

Reference:

1. Israel Klich and Leonid Levitov, "Quantum Noise as an Entanglement Meter", Phys. Rev. Lett. 102, 100502 (2009).
2. L. S. Levitov and G. B. Lesovik, "Charge distribution in quantum shot noise", JETP Lett. 58, 230 (1993). Translated from Pis'ma Zh. Eksp. Teor. Fiz. 58, 225 (1993).