152 citations · 2.3k across the 94 of their papers we have counts for
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Quantum Energy Inequalities with a twist: rotating frames along stationary worldlines
Christopher J. Fewster, Daniel Lomax Ford
The energy densities of the quantised scalar and electromagnetic fields need not be positive, but their averages along timelike worldlines are constrained by Quantum Energy Inequal…
When one sign is not enough: 2+1 circular motion Unruh effect at low energies
Leo J. A. Parry, Christopher J. Fewster, Jorma Louko
We address the circular motion Unruh effect in 2+1 spacetime dimensions, as probed by a pointlike Unruh-DeWitt detector coupled to a massless scalar field. The effective temperatur…
Measurement and preparation protocols for quantum field theory on curved spacetimes
Christopher J. Fewster
In this conference proceedings contribution, I describe work in progress concerning two problems in the measurement theory of quantum fields. First, it is proved that all local obs…
Waiting around for Unruh
Leo J. A. Parry, Diego Vidal-Cruzprieto, Christopher J. Fewster +1
How long does a uniformly rotating observer need to interact with a quantum field in order to register an approximately thermal response due to the circular motion Unruh effect? We…
Lectures on measurement in quantum field theory
Christopher J. Fewster
These lectures present a brief introduction to measurement theory for QFT in possibly curved spacetimes introduced by the author and R. Verch [Comm. Math. Phys. 378 (2020) 851-889]…
A semiclassical singularity theorem
Christopher J. Fewster, Eleni-Alexandra Kontou
Quantum fields do not satisfy the pointwise energy conditions that are assumed in the original singularity theorems of Penrose and Hawking. Accordingly, semiclassical quantum gravi…
Local Structure of Sprinkled Causal Sets
Christopher J. Fewster, Eli Hawkins, Christoph Minz +1
We describe numerical and analytical investigations of causal sets sprinkled into spacetime manifolds. The first part of the paper is a numerical study of finite causal sets sprink…
A new derivation of singularity theorems with weakened energy hypotheses
Christopher J. Fewster, Eleni-Alexandra Kontou
The original singularity theorems of Penrose and Hawking were proved for matter obeying the Null Energy Condition or Strong Energy Condition respectively. Various authors have prov…
A generally covariant measurement scheme for quantum field theory in curved spacetimes
Christopher J. Fewster
We propose and develop a measurement scheme for quantum field theory (QFT) in curved spacetimes, in which the QFT of interest, the "system", is dynamically coupled to another, the…
Classical and quantum strong energy inequalities and the Hawking singularity theorem
P. J. Brown, C. J. Fewster, E. -A. Kontou
Hawking's singularity theorem concerns matter obeying the strong energy condition (SEC), which means that all observers experience a non-negative effective energy density (EED). Th…
Quantum strong energy inequalities
Christopher J. Fewster, Eleni-Alexandra Kontou
Quantum energy inequalities (QEIs) express restrictions on the extent to which weighted averages of the renormalized energy density can take negative expectation values within a qu…
A singularity theorem for Einstein-Klein-Gordon theory
Peter J. Brown, Christopher J. Fewster, Eleni-Alexandra Kontou
Hawking's singularity theorem concerns matter obeying the strong energy condition (SEC), which means that all observers experience a nonnegative effective energy density (EED), the…
The art of the state
Christopher J. Fewster
Quantum field theory on curved spacetimes lacks an obvious distinguished vacuum state. We review a recent no-go theorem that establishes the impossibility of finding a preferred st…
Waiting for Unruh
Christopher J. Fewster, Benito A. Juárez-Aubry, Jorma Louko
How long does a uniformly accelerated observer need to interact with a quantum field in order to record thermality in the Unruh temperature? We address this question for a pointlik…
Locally covariant quantum field theory and the spin-statistics connection
Christopher J. Fewster
The framework of locally covariant quantum field theory, an axiomatic approach to quantum field theory in curved spacetime, is reviewed. As a specific focus, the connection between…
Locally covariant quantum field theory and the problem of formulating the same physics in all spacetimes
Christopher J. Fewster
The framework of locally covariant quantum field theory is discussed, motivated in part using "ignorance principles". It is shown how theories can be represented by suitable functo…
Probability distributions for quantum stress tensors in two and four dimensions
Christopher J. Fewster, L. H. Ford, Thomas A. Roman
The probability distributions for the smeared energy densities of quantum fields, in the two and four-dimensional Minkowski vacuum are discussed. These distributions share the prop…
Quantum fields in curved space-time, semiclassical gravity, quantum gravity phenomenology, and analogue models: Report on session D4 at GR20
Christopher J Fewster, Stefano Liberati
The talks given in parallel session D4 at the 20th International Conference on General Relativity and Gravitation (Warsaw 2013) are summarized.
The Necessity of the Hadamard Condition
Christopher J Fewster, Rainer Verch
Hadamard states are generally considered as the physical states for linear quantized fields on curved spacetimes, for several good reasons. Here, we provide a new motivation for th…
Lectures on quantum energy inequalities
Christopher J. Fewster
Quantum field theory violates all the classical energy conditions of general relativity. Nonetheless, it turns out that quantum field theories satisfy remnants of the classical ene…
Singularity theorems from weakened energy conditions
Christopher J. Fewster, Gregory J. Galloway
We establish analogues of the Hawking and Penrose singularity theorems based on (a) averaged energy conditions with exponential damping; (b) conditions on local stress-energy avera…
Quantum Energy Inequalities for the Non-Minimally Coupled Scalar Field
C. J. Fewster, L. W. Osterbrink
In this paper we discuss local averages of the energy density for the non-minimally coupled scalar quantum field, extending a previous investigation of the classical field. By an e…
Absolute quantum energy inequalities in curved spacetime
Christopher J. Fewster, Calvin J. Smith
Quantum Energy Inequalities (QEIs) are results which limit the extent to which the smeared renormalised energy density of the quantum field can be negative, when averaged along a t…
Averaged null energy condition in spacetimes with boundaries
Christopher J. Fewster, Ken D. Olum, Michael J. Pfenning
The Averaged Null Energy Condition (ANEC) requires that the average along a complete null geodesic of the projection of the stress-energy tensor onto the geodesic tangent vector ca…