58 citations · 302 across the 12 of their papers we have counts for
11 papers · 1 filter
Necessary and sufficient conditions for macrorealism using two and three-time Leggett-Garg inequalities
J. J. Halliwell
The Leggett-Garg (LG) inequalities were introduced, as a temporal parallel of the Bell inequalities, to test macroscopic realism -- the view that a macroscopic system evolving in t…
Comparing Conditions for Macrorealism: Leggett-Garg Inequalities vs No-Signaling in Time
J. J. Halliwell
We consider two different types of conditions which were proposed to test macrorealism in the context of a system described by a single dichotomic variable Q. This is the view that…
Deccoherent Histories and Measurement of Temporal Correlation Functions for Leggett-Garg Inequalities
J. J. Halliwell
We consider two protocols for the measurement of the temporal correlation functions of a dichotomic variable Q appearing in Leggett-Garg type inequalities. The protocols measure so…
An Introduction to the Quantum Backflow Effect
J. M. Yearsley, J. J. Halliwell
We present an introduction to the backflow effect in quantum mechanics -- the phenomenon in which a state consisting entirely of positive momenta may have negative current and the…
Amplitudes for Spacetime Regions and the Quantum Zeno Effect: Pitfalls of Standard Path Integral Constructions
J. J. Halliwell, J. M. Yearsley
We argue that under very general conditions, there is a significant complication in amplitudes for spacetimes regions constructed from path integrals. This is the fact that the con…
Negative Probabilities, Fine's Theorem and Linear Positivity
J. J. Halliwell, J. M. Yearsley
Many situations in quantum theory and other areas of physics lead to quasi-probabilities which seem to be physically useful but can be negative. The interpretation of such objects…
Quantum Arrival and Dwell Times via Idealised Clocks
J. M. Yearsley, D. A. Downs, J. J. Halliwell +1
A number of approaches to the problem of defining arrival and dwell time probabilities in quantum theory make use of idealised models of clocks. An interesting question is the exte…
On the Relationship Between Complex Potentials and Strings of Projection Operators
J. J. Halliwell, J. M. Yearsley
It is of interest in a variety of contexts, and in particular in the arrival time problem, to consider the quantum state obtained through unitary evolution of an initial state regu…
Quantum Arrival Time Formula from Decoherent Histories
J. J. Halliwell, J. M. Yearsley
In the arrival time problem in quantum mechanics, a standard formula that frequently emerges as the probability for crossing the origin during a given time interval is the current…
Arrival Times, Complex Potentials and Decoherent Histories
J. J. Halliwell, J. M. Yearsley
We address a number of aspects of the arrival time problem defined using a complex potential of step function form. We concentrate on the limit of a weak potential, in which the re…
Path Integral Analysis of Arrival Times with a Complex Potential
J. J. Halliwell
A number of approaches to the arrival time problem employ a complex potential of a simple step function type and the arrival time distribution may then be calculated using the stat…