109 citations · 1.3k across the 42 of their papers we have counts for
29 papers · 1 filter
Leggett-Garg violations for continuous variable systems with gaussian states
Clement Mawby, Jonathan Halliwell
Macrorealism (MR) is the world view that certain quantities may take definite values at all times irrespective of past or future measurements and may be experimentally falsified vi…
Leggett-Garg tests for macrorealism in the quantum harmonic oscillator and more general bound systems
Clement Mawby, Jonathan Halliwell
The Leggett-Garg (LG) inequalities were introduced to test for the possible presence of macroscopic quantum coherence. Since such effects may be found in various types of macroscop…
Detecting violations of macrorealism when the original Leggett-Garg inequalities are satisfied
Shayan Majidy, Jonathan J. Halliwell, Raymond Laflamme
Macroscopic realism (MR) is the notion that a time-evolving system possesses definite properties, irrespective of past or future measurements. Quantum mechanical theories can, howe…
Conditions for Macrorealism for Systems Described by Many-Valued Variables
J. J. Halliwell, C. Mawby
Macrorealism (MR) is the view that a system evolving in time possesses definite properties independent of past or future measurements and is traditionally tested for systems descri…
Exploration of an augmented set of Leggett-Garg inequalities using a noninvasive continuous-in-time velocity measurement
Shayan-Shawn Majidy, Hemant Katiyar, Galit Anikeeva +2
Macroscopic realism (MR) is the view that a system may possess definite properties at any time independent of past or future measurements, and may be tested experimentally using th…
Fine's Theorem for Leggett-Garg tests with an arbitrary number of measurement times
J. J. Halliwell, C. Mawby
If the time evolution of a system can be understood classically, then there must exist an underlying probability distribution for the variables describing the system at all times.…
A quasi-probability for the arrival time problem with links to backflow and the Leggett-Garg inequalities
J. J. Halliwell, H. Beck, B. K. B. Lee +1
The arrival time problem for the free particle in one dimension may be formulated as the problem of determining a joint probability for the particle being found on opposite sides o…
Incompatible Multiple Consistent Sets of Histories and Measures of Quantumness
J. J. Halliwell
In the consistent histories (CH) approach to quantum theory probabilities are assigned to histories subject to a consistency condition of negligible interference. The approach has…
Leggett-Garg Correlation Functions from Non-Invasive Velocity Measurement Continuous in Time
J. J. Halliwell
In the Leggett-Garg approach to testing macrorealism, the two-time correlation functions, which are normally obtained by sequential measurements of a dichotomic variable Q, need to…
The Leggett-Garg Inequalities and No-Signalling in Time: A Quasi-Probability Approach
J. J. Halliwell
The Leggett-Garg (LG) inequalities were proposed in order to assess whether sets of pairs of sequential measurements on a single quantum system can be consistent with an underlying…
A self-adjoint arrival time operator inspired by measurement models
J. J. Halliwell, J. Evaeus, J. London +1
We introduce an arrival time operator which is self-adjoint and, unlike previously proposed arrival time operators, has a close link to simple measurement models. Its spectrum lead…
Two Proofs of Fine's Theorem
J. J. Halliwell
Fine's theorem concerns the question of determining the conditions under which a certain set of probabilities for pairs of four bivalent quantities may be taken to be the marginals…
Classical Limit of the Quantum Zeno Effect by Environmental Decoherence
D. J. Bedingham, J. J. Halliwell
We consider a point particle in one dimension initially confined to a finite spatial region whose state is frequently monitored by projection operators onto that region. In the lim…
Quantum Backflow States from Eigenstates of the Regularized Current Operator
J. J. Halliwell, E. Gillman, O. Lennon +2
We present an exhaustive class of states with quantum backflow -- the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probabil…
Suppression of quantum-mechanical reflection by environmental decoherence
D. J. Bedingham, J. J. Halliwell
In quantum mechanics an incoming particle wave packet with sufficient energy will undergo both transmission and reflection when encountering a barrier of lower energy, but in class…
Partial Decoherence of Histories and the Diosi Test
J. J. Halliwell
In the decoherent histories approach to quantum theory, attention focuses on the conditions under which probabilities may be assigned to sets of quantum histories. A variety of con…
Macroscopic Superpositions, Decoherent Histories and the Emergence of Hydrodynamic Behaviour
J. J. Halliwell
Macroscopic systems are described most completely by local densities (particle number, momentum and energy) yet the superposition states of such physical variables, indicated by th…
Emergent Classicality via Commuting Position and Momentum Operators
J. J. Halliwell
Any account of the emergence of classicality from quantum theory must address the fact that the quantum operators representing positions and momenta do not commute, whereas their c…
Two Derivations of the Master Equation of Quantum Brownian Motion
J. J. Halliwell
Central to many discussion of decoherence is a master equation for the reduced density matrix of a massive particle experiencing scattering from its surrounding environment, such a…
Some Recent Developments in the Decoherent Histories Approach to Quantum Theory
J. J. Halliwell
A brief introduction to the decoherent histories approach to quantum theory is given, with emphasis on its role in the discussion of the emergence of classicality from quantum theo…
Approximate Decoherence of Histories and 't Hooft's Deterministic Quantum Theory
J. J. Halliwell
This paper explores the possibility that an exactly decoherent set of histories may be constructed from an approximately decoherent set by small distortions of the operators charac…
The Emergence of Hydrodynamic Equations from Quantum Theory: A Decoherent Histories Analysis
J. J. Halliwell
The most general description of the classical world is in terms of local densities (such as number, momentum, energy), and these typically evolve according to evolution equations o…
Decoherent Histories and the Emergent Classicality of Local Densities
J. J. Halliwell
In the context of the decoherent histories approach to quantum theory, it is shown that a class of macroscopic configurations consisting of histories of local densities (number, mo…
Somewhere in the Universe: Where is the Information Stored When Histories Decohere?
J. J. Halliwell
We investigate the idea that decoherence is connected with the storage of information about the decohering system somewhere in the universe. The known connection between decoherenc…