A major conceptual achievement of Einstein’s theory of relativity is the understanding that space and time arise from a single physical entity, spacetime. Within spacetime, the distinction between space and time is operated by what one calls the causal structure. The objective of our research is to identify the fate of this causal structure at …
A clock on the ground floor runs slower than a clock on the top floor; this is one of the effects of spacetime curvature caused by our planet’s mass. The effect is minuscule by human standards, but it is a real effect with measurable implications for satellite technology. In [2], it was pointed out that …
The multimode collaborative work `Non-gaussianity as a Signature of a Quantum Theory of Gravity’ between Hong Kong, Aix-Marseille and Oxford you, lead by Richard Howl and with the participation of Marios Christodoulou, Carlo Rovelli and Vlatko Vedral, has been published in PRX Quantum. Below is an accessible to the non-specialist summary. For over a hundred years, physicists …
Testing for Quantum Gravity with Bose-Einstein Condensates Read More »
By Giulio Chiribella and Zixuan Liu. Pre-publication link. At the microscopic level, the fundamental laws of physics are time symmetric: every fundamental process admits a time-reversal, which describes the same physics seen from the point of view of an observer with an inverted arrow of time. In stark contrast, our everyday experience and our laboratory practice …
When we think operationally about space and time, we usually assume that the objects we use as reference frames are classical systems – like a macroscopic heavy ruler or a clock with sharply defined hands. Quantum reference frames have recently been introduced as a formalism to describe physics when rulers and clocks are assumed to …
Witnessing non-classicality beyond quantum theory. Published in Physical Review D. By Chiara Marletto (QISS Oxford Physics) and Vlatko Vedral (QISS Oxford Physics). Popular Summary: This paper provides the strongest theoretical basis for recently proposed experiments to test quantum effects in gravity, achieving the remarkable result that such experiments, if performed successfully, would rule out all …
Witnessing non-classicality beyond quantum theory Read More »
Quantum information and the arrow of time. Andrea Di Biagio (QISS Rome), Pietro Donà, Carlo Rovelli (QISS Marseille) pre-published at Popular Summary: Standard formulations of quantum mechanics feature two distinct laws describing how the state of a quantum system changes in time. The first law, the Schrödinger equation, is smooth and time-reversal symmetric. By looking …
Cognitive Structures of Space-Time. Published in Frontiers in Psychology, 21 October 2020. By Signorelli Camilo Miguel, Dündar-Coecke Selma, Wang Vincent, Coecke Bob (QISS Oxford Computer Science) Popular Summary Space and time have been the subject of physics for thousands of years, with Euclid’s account paving the way for modern mathematics. At the same time it …
[1] Facts are relative, Caslav Brukner, Nature Physics volume 16, pages 1172–1174 (2020), [2] A no-go theorem for the persistent reality of Wigner’s friend’s perception (under review) Popular summary: The quantum measurement problem is one of the most fundamental in quantum theory and its putative solutions are at the centre of controversy over their alternative interpretations. …
Wigner’s friend through experiment: relativity of facts Read More »
[1] Time’s Arrow of a Quantum Superposition of Thermodynamic Evolutions. By G. Rubino , G. Manzano, and C. Brukner Fundamental laws of physics are generally time-symmetric. The directionality of time is then often explained with the thermodynamic arrow of time: the entropy of an isolated system increases during a process, and it is constant only …
The superpositions of thermodynamical arrows of time Read More »
QISS is a cross–disciplinary fundamental research initiative in the broader fields of Quantum Information and Quantum Gravity.
