Path of a tunneling particle

Abstract

Attempts to find a quantum-to-classical correspondence in a classically forbidden region leads to non-physical paths, involving, for example, complex time or spatial coordinates. Here, we identify genuine quasi-classical paths for tunneling in terms of probabilistic correlations in sequential time-of-arrival measurements. In particular, we construct the post-selected probability density P p.s.

Quantum Information in Relativity: The Challenge of QFT Measurements

“…In this section, we describe the QTP approach to QFT measurements, which we have been developing for a number of years [ 9 , 10 , 11 , 87 , 88 ]. The QTP approach aims to construct a framework for measurements that (i) works, in principle, for any QFT, (ii) allows for a first-principles investigation of all issues of causality and locality in relation to QFT measurements, and (iii) it can be directly applied to experiments of current interest.…”

“…For n detection events at spacetime points , the QTP probability density is where are kernels associated to the n detectors, and is a -point function of which the first n indices are anti-time-ordered and the last n indices are time-ordered. Versions of Equation ( 11 ) have been employed for the analysis of temporal aspects of quantum entanglement in non-relativistic systems [ 10 ], quasi-classical paths in quantum tunneling [ 88 ], and correlations in Hawking radiation [ 8 ].…”

Quantum Information in Relativity: the Challenge of QFT Measurements

“…Versions of Eq. ( 11) gave been employed for the analysis of temporal aspects of quantum entanglement in non-relativistic systems [9], quasi-classical paths in quantum tunneling [58], and correlations in Hawking radiation [6].…”

Qubit-based momentum measurement of a particle

“…Pointer systems representing measurement devices were included into the description of the measurement process. Hence, it is interesting to ask whether this idea allows us to assign basic classical concepts like timeof-flight (ToF) measurements an operational meaning in quantum mechanics [18][19][20][21][22][23][24][25]. In contrast to Ref.…”