Physics and Astronomy - Quantum Nano Seminar - Jay Lawrence, Dartmouth College

Title: "Observing A Quantum Measurement"

February 14, 2019
4 pm - 5 pm
Location
Wilder 202
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854

ABSTRACT: The quantum measurement problem has been stated (review of M. Schlosshauer, 2018) as “the question of how to reconcile the linear, deter- ministic evolution described by the Schr ̈odinger equation with the occurrence of random measurement outcomes,” I will address this question with a varia- tion on the Von Neumann measurement picture as informed by decoherence theory. Envisioning the usual Stern-Gerlach scenario, the variation replaces the canonical “pointer” with an array of quantum two-state systems, one along each path, which can be read out (“observed”) with recording devices (a gedanken experiment which can actually be done). With this arrange- ment, one can choose to “observe” the usual collapse scenario in which the particle chooses one path to the exclusion of the other - or, on the identically prepared state, the superposition of both paths. The model shows why “clas- sical” detectors alone cannot see the superposition. It also clarifies the role of decoherence in “controlled” Von Neumann-type measurements, and shows that the pointer basis of the apparatus is chosen by the observer, not the environment as held by current decoherence theories.

Location
Wilder 202
Sponsored by
Physics & Astronomy Department
Audience
Public
More information
Tressena Manning
603-646-2854