186 citations · 1.2k across the 27 of their papers we have counts for
27 papers
Testing the weak equivalence principle for nonclassical matter with torsion balances
Roberto Onofrio, Alexander R. H. Smith, Lorenza Viola
We propose tests of the weak equivalence principle (WEP) using a torsion balance, in which superposition of energy eigenstates are created in a controllable way for the test masses…
Matter relative to quantum hypersurfaces
Philipp A. Hoehn, Andrea Russo, Alexander R. H. Smith
We explore the canonical description of a scalar field as a parameterized field theory on an extended phase space that includes additional embedding fields that characterize spacet…
Quantum time dilation in a gravitational field
Jerzy Paczos, Kacper Dębski, Piotr T. Grochowski +2
According to relativity, the reading of an ideal clock is interpreted as the elapsed proper time along its classical trajectory through spacetime. In contrast, quantum theory allow…
Finite resolution ancilla-assisted measurements of quantum work distributions
Shadi Ali Ahmad, Alexander R. H. Smith
Work is an observable quantity associated with a process, however there is no Hermitian operator associated with its measurement. We consider an ancilla-assisted protocol measuring…
Quantum Relativity of Subsystems
Shadi Ali Ahmad, Thomas D. Galley, Philipp A. Hoehn +2
One of the most basic notions in physics is the partitioning of a system into subsystems, and the study of correlations among its parts. In this work, we explore these notions in t…
Equivalence of approaches to relational quantum dynamics in relativistic settings
Philipp A. Hoehn, Alexander R. H. Smith, Maximilian P. E. Lock
We have previously shown (arXiv:1912.00033) that three approaches to relational quantum dynamics -- relational Dirac observables, the Page-Wootters formalism and quantum deparametr…
Gravitational waves affect vacuum entanglement
Qidong Xu, Shadi Ali Ahmad, Alexander R. H. Smith
The entanglement harvesting protocol is an operational way to probe vacuum entanglement. This protocol relies on two atoms, modelled by Unruh-DeWitt detectors, that are initially u…
Quantum time dilation in atomic spectra
Piotr T. Grochowski, Alexander R. H. Smith, Andrzej Dragan +1
Quantum time dilation occurs when a clock moves in a superposition of relativistic momentum wave packets. We utilize the lifetime of an excited hydrogen-like atom as a clock to dem…
Quantum time dilation: A new test of relativistic quantum theory
Alexander R. H. Smith
A novel quantum time dilation effect is shown to arise when a clock moves in a quantum superposition of two relativistic velocities. This effect is argued to be measurable using ex…
The Trinity of Relational Quantum Dynamics
Philipp A. Hoehn, Alexander R. H. Smith, Maximilian P. E. Lock
The problem of time in quantum gravity calls for a relational solution. Using quantum reduction maps, we establish a previously unknown equivalence between three approaches to rela…
The BTZ black hole exhibits anti-Hawking phenomena
Laura J. Henderson, Robie A. Hennigar, Robert B. Mann +2
The Unruh effect is a surprising prediction of quantum field theory that asserts accelerating observers perceive a thermal spectrum of particles with a temperature proportional to…
Generalized probability rules from a timeless formulation of Wigner's friend scenarios
Veronika Baumann, Flavio Del Santo, Alexander R. H. Smith +3
The quantum measurement problem can be regarded as the tension between the two alternative dynamics prescribed by quantum mechanics: the unitary evolution of the wave function and…
Quantum satellites and tests of relativity
Piergiovanni Magnani, Matteo Schiavon, Alexander R. H. Smith +5
Deployment of quantum technology in space provides opportunities for new types of precision tests of gravity. On the other hand, the operational demands of such technology can make…
Communicating without shared reference frames
Alexander R. H. Smith
We generalize a quantum communication protocol introduced by Bartlett et al. [New. J. Phys. 11, 063013 (2009)] in which two parties communicating do not share a classical reference…
Proposal for an optical interferometric measurement of the gravitational red-shift with satellite systems
Daniel R. Terno, Francesco Vedovato, Matteo Schiavon +4
The Einstein Equivalence Principle (EEP) underpins all metric theories of gravity. One of its key aspects is the local position invariance (LPI) of non-gravitational experiments, w…
Entangling detectors in anti-de Sitter space
Laura J. Henderson, Robie A. Hennigar, Robert B. Mann +2
We examine in -dimensional anti-de Sitter (AdS) space the phenomena of entanglement harvesting - the process in which a pair of detectors (two-level atoms) extract entanglem…
Harvesting Entanglement from the Black Hole Vacuum
Laura J. Henderson, Robie A. Hennigar, Robert B. Mann +2
We implement the entanglement harvesting protocol, in which two Unruh-DeWitt detectors become entangled through local interactions with a quantum field, for the first time in the v…
Quantizing time: Interacting clocks and systems
Alexander R. H. Smith, Mehdi Ahmadi
This article generalizes the conditional probability interpretation of time in which time evolution is realized through entanglement between a clock and a system of interest. This…
Massive Unruh particles cannot be directly observed
Filip Kiałka, Alexander R. H. Smith, Mehdi Ahmadi +1
We show that massive particles created in a relativistically accelerated reference frame, as predicted by the Unruh effect, can only be found in a tiny layer above the event horizo…
Quantum reference frames associated with non-compact groups: the case of translations and boosts, and the role of mass
Alexander R. H. Smith, Marco Piani, Robert B. Mann
Quantum communication without a shared reference frame or the construction of a relational quantum theory requires the notion of a quantum reference frame. We analyze aspects of qu…
Effect of relativistic acceleration on localized two-mode Gaussian quantum states
Mehdi Ahmadi, Krzysztof Lorek, Agata Chęcińska +3
We study how an arbitrary Gaussian state of two localized wave packets, prepared in an inertial frame of reference, is described by a pair of uniformly accelerated observers. We ex…
Communication between inertial observers with partially correlated reference frames
Mehdi Ahmadi, Alexander R. H. Smith, Andrzej Dragan
In quantum communication protocols the existence of a shared reference frame between two spatially separated parties is normally presumed. However, in many practical situations we…
Spacetime structure and vacuum entanglement
Eduardo Martin-Martinez, Alexander R. H. Smith, Daniel R. Terno
We study the role that both vacuum fluctuations and vacuum entanglement of a scalar field play in identifying the spacetime topology, which is not prescribed from first principles-…
Post-Newtonian gravitational effects in quantum interferometry
Aharon Brodutch, Alexei Gilchrist, Thomas Guff +2
We investigate general properties of optical interferometry in stationary spacetimes and apply the obtained results focusing on quantum-optical experiments in near-Earth environmen…