Results 61 to 70 of about 165,231 (345)

The Feynman propagator for quantum gravity: spin foams, proper time, orientation, causality and timeless-ordering

open access: yes, 2004
We discuss the notion of causality in Quantum Gravity in the context of sum-over-histories approaches, in the absence therefore of any background time parameter.
Oriti, Daniele
core   +4 more sources

Towards the map of quantum gravity [PDF]

open access: yes, 2018
In this paper we point out some possible links between different approaches to quantum gravity and theories of the Planck scale physics. In particular, connections between Loop Quantum Gravity, Causal Dynamical Triangulations, Ho\v{r}ava-Lifshitz gravity,
Mielczarek, Jakub, Trześniewski, Tomasz
core   +2 more sources

An Atomic‐Level Bimetallic MOF Platform Overcoming the Stability‐Performance Tradeoff for Laser Propulsion

open access: yesAdvanced Materials, EarlyView.
This work introduces an atomic‐level engineered bimetallic MOF Platform that resolves the inherent trade‐off between environmental stability and propulsion efficiency. By integrating robust Fe‐O bonds for hydrolysis resistance and enabling d‐orbital charge transfer (Fe3+→Cu2+) for enhanced photothermal conversion, the design achieves a highly durable ...
Senlin Rao   +3 more
wiley   +1 more source

Photocatalytic Water Splitting on the Lunar Surface: Prospects for In Situ Resource Utilization

open access: yesAdvanced Materials Interfaces, EarlyView.
Water has been found in craters on the moon nearby locations which are illuminated >80% of the time. Photocatalysis uses energy from sunlight to drive chemical reactions such as water splitting to produce oxygen and hydrogen. It is a scalable technology that requires lighter equipment and utilizes resources available on the moon. ABSTRACT The discovery
Ranjani Kalyan   +6 more
wiley   +1 more source

What is the curvature of 2D Euclidean quantum gravity?

open access: yesJournal of High Energy Physics
We re-examine the nonperturbative curvature properties of two-dimensional Euclidean quantum gravity, obtained as the scaling limit of a path integral over dynamical triangulations of a two-sphere, which lies in the same universality class as Liouville ...
R. Loll, T. Niestadt
doaj   +1 more source

A solvable model of flat space holography

open access: yesJournal of High Energy Physics, 2023
We propose an explicit realization of flat space holography in two dimensions where both sides of the duality are independently defined and the boundary theory is completely solvable.
Felipe Rosso
doaj   +1 more source

Waveguide Photoactuators: Materials, Fabrication, and Applications

open access: yesAdvanced Robotics Research, EarlyView.
Waveguide photoactuators convert guided light into mechanical motion. Their tethered‐flexible design enables minimally invasive surgery and confined‐space robotics. This review aims to guide materials selection, device design, and system integration, accelerating the transition of waveguide photoactuators from laboratory prototypes to versatile ...
Minjie Xi   +4 more
wiley   +1 more source

Off-shell unimodular N = 1, d = 4 supergravity

open access: yesJournal of High Energy Physics, 2020
We formulate a unimodular N = 1, d = 4 supergravity theory off shell. We see that the infinitesimal Grassmann parameters defining the unimodular supergravity trans- formations are constrained and show that the conmutator of two infinitesinal unimodular ...
Jesus Anero   +2 more
doaj   +1 more source

A model of quantum collapse induced by gravity [PDF]

open access: yesThe European Physical Journal D, 2020
Version pubished in ...
openaire   +2 more sources

Towards a spin foam model description of black hole entropy

open access: yes, 2008
We propose a way to describe the origin of black hole entropy in the spin foam models of quantum gravity. This stimulates a new way to study the relation of spin foam models and loop quantum gravity.Comment: 5 pages, 1 ...
Corichi A   +7 more
core   +1 more source

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