scholarly journals Prospects for Studies of the Free Fall and Gravitational Quantum States of Antimatter

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
G. Dufour ◽  
D. B. Cassidy ◽  
P. Crivelli ◽  
P. Debu ◽  
A. Lambrecht ◽  
...  
Keyword(s):  
Free Fall ◽  
Quantum States ◽  
Experimental Techniques ◽  
Ultracold Neutrons ◽  
Neutral System ◽  
Close Analogy ◽  
Quantum Reflection ◽  
The Status ◽  
Neutral Antimatter ◽  
Ultimate Limit

Different experiments are ongoing to measure the effect of gravity on cold neutral antimatter atoms such as positronium, muonium, and antihydrogen. Among those, the project GBAR at CERN aims to measure precisely the gravitational fall of ultracold antihydrogen atoms. In the ultracold regime, the interaction of antihydrogen atoms with a surface is governed by the phenomenon of quantum reflection which results in bouncing of antihydrogen atoms on matter surfaces. This allows the application of a filtering scheme to increase the precision of the free fall measurement. In the ultimate limit of smallest vertical velocities, antihydrogen atoms are settled in gravitational quantum states in close analogy to ultracold neutrons (UCNs). Positronium is another neutral system involving antimatter for which free fall under gravity is currently being investigated at UCL. Building on the experimental techniques under development for the free fall measurement, gravitational quantum states could also be observed in positronium. In this contribution, we report on the status of the ongoing experiments and discuss the prospects of observing gravitational quantum states of antimatter and their implications.

scholarly journals Status of the GRANIT Facility

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Damien Roulier ◽  
Francis Vezzu ◽  
Stefan Baeßler ◽  
Benoît Clément ◽  
Daniel Morton ◽  
...  
Keyword(s):  
Particle Physics ◽  
Quantum States ◽  
Experimental Techniques ◽  
Current Status ◽  
Ultracold Neutrons

The GRANIT facility is a follow-up project, which is motivated by the recent discovery of gravitational quantum states of ultracold neutrons. The goal of the project is to approach the ultimate accuracy in measuring parameters of such quantum states and also to apply this phenomenon and related experimental techniques to a broad range of applications in particle physics as well as in surface and nanoscience studies. We overview the current status of this facility, the recent test measurements, and the nearest prospects.

QUANTUM STATES OF NEUTRONS IN THE EARTH'S GRAVITATIONAL FIELD: CONSTRAINTS FOR QUASI-ELASTIC REFLECTIONS IN THE RANGE ΔE~10-12–10-9eV

2005 ◽  
Vol 14 (03n04) ◽  
pp. 511-519 ◽  
Author(s):  
V. V. NESVIZHEVSKY
Keyword(s):  
Quantum Mechanics ◽  
Gravitational Field ◽  
Energy Range ◽  
Quantum States ◽  
Ultracold Neutrons ◽  
Neutron Spectrometry ◽  
Earth’S Gravitational Field ◽  
Elastic Process

A restrictive constraint for any quasi-elastic process was obtained in the previously inaccessible energy range ΔE~10-12–3·10-10 eV for reflections of ultracold neutrons from surfaces in the experiment on neutron quantum states in the earth's gravitational field. This could be useful for precision neutron spectrometry experiments and for the verification of extensions of quantum mechanics.

scholarly journals Quantized Ultracold Neutrons in Rough Waveguides: GRANIT Experiments and Beyond

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
M. Escobar ◽  
A. E. Meyerovich
Keyword(s):  
Surface Roughness ◽  
Quantum States ◽  
Scaling Relations ◽  
Ultracold Neutrons ◽  
System Parameters ◽  
Neutron Count ◽  
Simple Scaling ◽  
Biased Diffusion ◽  
Rough Boundaries ◽  
Single Constant

We apply our general theory of transport in systems with random rough boundaries to gravitationally quantized ultracold neutrons in rough waveguides as in GRANIT experiments (ILL, Grenoble). We consider waveguides with roughness in both two and one dimensions (2D and 1D). In the biased diffusion approximation the depletion times for the gravitational quantum states can be easily expressed via each other irrespective of the system parameters. The calculation of the exit neutron count reduces to evaluation of a single constant which contains a complicated integral of the correlation function of surface roughness. In the case of 1D roughness (random grating) this constant is calculated analytically for common types of the correlation functions. The results obey simple scaling relations which are slightly different in 1D and 2D. We predict the exit neutron count for the new GRANIT cell.

The geodetic precession as a 3D Schouten precession and a gravitational Thomas precession

2014 ◽  
Vol 92 (10) ◽  
pp. 1082-1093
Author(s):  
E.P.J. (Paul) de Haas
Keyword(s):  
B Physics ◽  
Parallel Transport ◽  
Free Fall ◽  
De Sitter ◽  
Thomas Precession ◽  
Gravity Probe B ◽  
Curved Space ◽  
Geodetic Precession ◽  
The Status ◽  
Gravity Probe

The Gravity Probe B (GP-B) experiment measured the geodetic precession due to parallel transport in a curved space–time metric, as predicted by de Sitter, Fokker, and Schiff. The Schiff treatment included Thomas precession and argued that it should be zero in a free fall orbit. We review the existing interpretations regarding the relation between the Thomas precession and the geodetic precession for a gyroscope in a free fall orbit. Schiff and Parker had contradictory views on the status of the Thomas precession in a free fall orbit, a contradiction that continues to exist in the literature. In the second part of this paper we derive the geodetic precession as a global Thomas precession by use of the equivalent principle and some elements of hyperbolic geometry, a derivation that allows the treatment of GP-B physics in between special and general relativity courses.

scholarly journals Gravitation at the Mesoscopic Scale

1997 ◽  
Vol 12 (19) ◽  
pp. 1411-1417 ◽  
Author(s):  
R. Onofrio ◽  
L. Viola
Keyword(s):  
Probability Distributions ◽  
Free Fall ◽  
Quantum States ◽  
Quantum Case ◽  
Initial State ◽  
Weak Equivalence Principle ◽  
Classical Counterpart ◽  
Inertial Frames ◽  
The Times ◽  
Accelerated Frames

Free fall experiments are discussed by using test masses associated to quantum states not necessarily possessing a classical counterpart. The times of flight of the Galilean experiments using classical test masses are replaced in the quantum case by probability distributions which, although still not defined in an uncontroversial manner, become manifestly dependent upon the mass and the initial state. Such a dependence is also expected in non-inertial frames of reference if the weak equivalence principle still holds. The latter could be tested, merging recent achievements in mesoscopic physics, by using cooled atoms in free fall and accelerated frames initially prepared in nonclassical quantum states.

scholarly journals A spectroscopy approach to measure the gravitational mass of antihydrogen

2014 ◽  
Vol 30 ◽  
pp. 1460266 ◽  
Author(s):  
A. Yu. Voronin ◽  
V. V. Nesvizhevsky ◽  
G. Dufour ◽  
P. Debu ◽  
A. Lambrecht ◽  
...  
Keyword(s):  
Applied Field ◽  
Free Fall ◽  
Time Measurement ◽  
Quantum States ◽  
Gravitational Mass ◽  
Spatial Density ◽  
Material Surface ◽  
A Value ◽  
The Earth ◽  
Resonant Transitions

We study a method to induce resonant transitions between antihydrogen [Formula: see text] quantum states above a material surface in the gravitational field of the Earth. The method consists of applying a gradient of magnetic field, which is temporally oscillating with the frequency equal to a frequency of transition between gravitational states of antihydrogen. A corresponding resonant change in the spatial density of antihydrogen atoms could be measured as a function of the frequency of applied field. We estimate an accuracy of measuring antihydrogen gravitational states spacing and show how a value of the gravitational mass of the [Formula: see text] atom could be deduced from such a measurement. We also demonstrate that a method of induced transitions could be combined with a free-fall-time measurement in order to further improve the precision.

A LABORATORY TEST OF THE EQUIVALENCE PRINCIPLE AS PROLOG TO A SPACEBORNE EXPERIMENT

2007 ◽  
Vol 16 (12a) ◽  
pp. 2245-2258 ◽  
Author(s):  
ROBERT D. REASENBERG ◽  
JAMES D. PHILLIPS
Keyword(s):  
Equivalence Principle ◽  
Degrees Of Freedom ◽  
Vacuum Chamber ◽  
Free Fall ◽  
Upward Motion ◽  
Principle Of Equivalence ◽  
Weak Equivalence Principle ◽  
Motion System ◽  
The Status ◽  
Capacitance Gauge

To test the equivalence principle (EP) to an accuracy of at least σ(Δ g)/g = 5 × 10-14, we are developing a modern Galilean experiment. In our principle-of-equivalence measurement (POEM), we directly examine the relative motion of two test mass assemblies (TMA) that are freely falling. Such an experiment tests both for a possible violation of the weak equivalence principle (WEP) and for new forces that might mimic a WEP violation. For the terrestrial version of the experiment, there are three key technologies. A laser gauge measures the separation of the TMA to picometer accuracy in a second as they fall freely in a comoving vacuum chamber. The motion system launches the TMA from their kinematic mounts inside the chamber and keeps the chamber on a trajectory that mimics free fall until the chamber nears the bottom of its motion. It then "bounces" the chamber back to upward motion in preparation for a new launch of the TMA. A capacitance gauge system measures an additional four degrees of freedom of the motion of each TMA. The resulting estimate of the rotation around and translation along the horizontal axes is used to correct systematic errors. We describe the status of POEM and discuss recent progress.

QUANTUMNESS OF ENSEMBLE FROM NO-BROADCASTING PRINCIPLE

2006 ◽  
Vol 04 (01) ◽  
pp. 105-118 ◽  
Author(s):  
MICHAł HORODECKI ◽  
PAWEł HORODECKI ◽  
RYSZARD HORODECKI ◽  
MARCO PIANI
Keyword(s):  
Quantum Information ◽  
Information Content ◽  
Quantum Physics ◽  
Single Copy ◽  
Quantum Systems ◽  
Quantum States ◽  
New Approach ◽  
Permanence Property ◽  
The Status ◽  
The Difference

Quantum information, though not precisely defined, is a fundamental concept of quantum information theory which predicts many fascinating phenomena and provides new physical resources. A basic problem is to recognize the features of quantum systems responsible for those phenomena. One of these important features is that non-commuting quantum states cannot be broadcast: two copies cannot be obtained out of a single copy, not even reproduced marginally on separate systems. We focus on the difference in information content between one copy and two copies, which is a basic manifestation of the gap between quantum and classical information. We show that if the chosen information measure is the Holevo quantity, the difference between the information content of one copy and two copies is zero if and only if the states can be broadcast. We propose a new approach in defining measures of quantumness of ensembles based on the difference in information content between the original ensemble and the ensemble of duplicated states. We comment on the permanence property of quantum states and the recently introduced superbroadcasting operation. We also provide an appendix where we discuss the status of quantum information in quantum physics, based on the so-called isomorphism principle.

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