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 Probability distributions of COVID-19 tweet posted trends use a nonhomogeneous Poisson process

2020 ◽  
Vol 1 (4) ◽  
pp. 229-238
Author(s):  
Devi Munandar ◽  
Sudradjat Supian ◽  
Subiyanto Subiyanto
Keyword(s):  
Social Media ◽  
Poisson Process ◽  
Exponential Distribution ◽  
Probability Distributions ◽  
Nonhomogeneous Poisson Process ◽  
Time Interval ◽  
Initial State ◽  
Time Intervals ◽  
Time Parameters ◽  
Parameter Values

The influence of social media in disseminating information, especially during the COVID-19 pandemic, can be observed with time interval, so that the probability of number of tweets discussed by netizens on social media can be observed. The nonhomogeneous Poisson process (NHPP) is a Poisson process dependent on time parameters and the exponential distribution having unequal parameter values and, independently of each other. The probability of no occurrence an event in the initial state is one and the probability of an event in initial state is zero. Using of non-homogeneous Poisson in this paper aims to predict and count the number of tweet posts with the keyword coronavirus, COVID-19 with set time intervals every day. Posting of tweets from one time each day to the next do not affect each other and the number of tweets is not the same. The dataset used in this study is crawling of COVID-19 tweets three times a day with duration of 20 minutes each crawled for 13 days or 39 time intervals. The result of this study obtained predictions and calculated for the probability of the number of tweets for the tendency of netizens to post on the situation of the COVID-19 pandemic.

FALLING RIGHT WHILE MOVING SLOW: TRUE TESTS OF THE WEAK EQUIVALENCE PRINCIPLE FOR ANTIPARTICLES

2012 ◽  
Vol 21 (11) ◽  
pp. 1242016
Author(s):  
C. S. UNNIKRISHNAN ◽  
G. T. GILLIES
Keyword(s):  
Equivalence Principle ◽  
Free Fall ◽  
Weak Equivalence ◽  
Surprising Result ◽  
Intrinsic Properties ◽  
Weak Equivalence Principle ◽  
Quantum Numbers ◽  
Supernova 1987A ◽  
Relativistic Factor ◽  
Cold Matter

A significant question in experimental gravity is the nature of free fall of antiparticles under gravity and elaborate preparations are underway to directly test this with cold antihydrogen. Earlier, the Shapiro delay of supernova 1987A neutrinos was interpreted as testing the weak equivalence principle (WEP). We establish the surprising result that the Shapiro delay of relativistic particles does not test WEP for intrinsic properties or quantum numbers of particles or antiparticles. This is because essentially the entire gravitational mass of the relativistic neutrinos is contributed by kinetic energy, diluting to insignificance any EP violating contribution from intrinsic properties, by the relativistic factor. The crucial message here is that a true test of the WEP involving intrinsic properties of matter or antimatter — the foundation of relativistic gravity — necessarily requires nonrelativistic "cold" matter and antimatter.

scholarly journals Quantum Generative Adversarial Networks for learning and loading random distributions

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Christa Zoufal ◽  
Aurélien Lucchi ◽  
Stefan Woerner
Keyword(s):  
Quantum State ◽  
Quantum Channel ◽  
Quantum Algorithms ◽  
Probability Distributions ◽  
Quantum Algorithm ◽  
Quantum Circuit ◽  
Quantum Simulation ◽  
Quantum States ◽  
Generative Adversarial Networks ◽  
Adversarial Networks

AbstractQuantum algorithms have the potential to outperform their classical counterparts in a variety of tasks. The realization of the advantage often requires the ability to load classical data efficiently into quantum states. However, the best known methods require $${\mathcal{O}}\left({2}^{n}\right)$$O2n gates to load an exact representation of a generic data structure into an $$n$$n-qubit state. This scaling can easily predominate the complexity of a quantum algorithm and, thereby, impair potential quantum advantage. Our work presents a hybrid quantum-classical algorithm for efficient, approximate quantum state loading. More precisely, we use quantum Generative Adversarial Networks (qGANs) to facilitate efficient learning and loading of generic probability distributions - implicitly given by data samples - into quantum states. Through the interplay of a quantum channel, such as a variational quantum circuit, and a classical neural network, the qGAN can learn a representation of the probability distribution underlying the data samples and load it into a quantum state. The loading requires $${\mathcal{O}}\left(poly\left(n\right)\right)$$Opolyn gates and can thus enable the use of potentially advantageous quantum algorithms, such as Quantum Amplitude Estimation. We implement the qGAN distribution learning and loading method with Qiskit and test it using a quantum simulation as well as actual quantum processors provided by the IBM Q Experience. Furthermore, we employ quantum simulation to demonstrate the use of the trained quantum channel in a quantum finance application.

Quantum circuits for calculating the squared sum of the inner product of quantum states and its application

2019 ◽  
Vol 17 (05) ◽  
pp. 1950043
Author(s):  
Panchi Li ◽  
Jiahui Guo ◽  
Bing Wang ◽  
Mengqi Hao
Keyword(s):  
Quantum Circuit ◽  
Quantum States ◽  
Experimental Results ◽  
Quantum Circuits ◽  
Inner Product ◽  
Superposition State ◽  
Initial State ◽  
Control Rules ◽  
Control Qubit ◽  
Classical Computer

In this paper, we propose a quantum circuit for calculating the squared sum of the inner product of quantum states. The circuit is designed by the multi-qubits controlled-swapping gates, in which the initial state of each control qubit is [Formula: see text] and they are in the equilibrium superposition state after passing through some Hadamard gates. Then, according to the control rules, each basis state in the superposition state controls the corresponding quantum states pair to swap. Finally, the Hadamard gates are applied to the control qubits again, and the squared sum of the inner product of many pairs of quantum states can be obtained simultaneously by measuring only one control qubit. We investigate the application of this method in quantum images matching on a classical computer, and the experimental results verify the correctness of the proposed method.

Antihydrogen physics: gravitation and spectroscopy in AEgISThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at École de Physique, les Houches, France, 30 May – 4 June, 2010.

2011 ◽  
Vol 89 (1) ◽  
pp. 17-24 ◽  
Author(s):  
R. Ferragut ◽  
A. S. Belov ◽  
G. Bonomi ◽  
I. Boscolo ◽  
R. S. Brusa ◽  
...  
Keyword(s):  
Equivalence Principle ◽  
Stark Effect ◽  
Rydberg State ◽  
Free Fall ◽  
Second Phase ◽  
General Description ◽  
Exchange Reactions ◽  
Weak Equivalence Principle ◽  
Atomic Systems ◽  
Subsequent Measurement

AEgIS (Antimatter experiment: gravity, interferometry, spectroscopy) is an experiment approved by CERN with the goal of studying antihydrogen physics. In AEgIS, antihydrogen will be produced by charge exchange reactions of cold antiprotons with positronium atoms excited in a Rydberg state (n > 20). In the first phase of the experiment, controlled acceleration by an electric field gradient (Stark effect) and subsequent measurement of free fall in a Moiré deflectometer will allow a test of the weak equivalence principle. In a second phase, the antihydrogen will be slowed, confined, and laser-cooled to perform CPT studies and detailed spectroscopy. In the present work, after a general description of the experiment, the present status of advancement will be reviewed, with special attention to the production and excitation of positronium atoms.

scholarly journals Microscope – A space mission to test the equivalence principle

2009 ◽  
Vol 5 (S261) ◽  
pp. 423-425 ◽  
Author(s):  
Meike List ◽  
Hanns Selig ◽  
Stefanie Bremer ◽  
Claus Lämmerzahl
Keyword(s):  
High Precision ◽  
Equivalence Principle ◽  
Free Fall ◽  
Space Mission ◽  
Drop Tower ◽  
Weak Equivalence ◽  
Weak Equivalence Principle ◽  
Space Agency

AbstractMICROSCOPE is a ESA/CNES space mission for testing the validity of the weak equivalence principle. The mission's goal is to determine the Eötvös parameter η with an accuracy of 10−15. The French space agency CNES is responsible for designing the satellite which is developed and produced within the Myriade series. The satellite's payload T–SAGE (Twin Space Accelerometer for Gravitation Experimentation) consists of two high–precision capacitive differential accelerometers and is developed and built by the French institute ONERA.As a member of the MICROSCOPE performance team, the German department ZARM performs free fall tests of the MICROSCOPE differential accelerometers at the Bremen drop tower. The project's concepts and current results of the free fall tests are shortly presented.

Constraints on gravitational properties of antimatter from cyclotron-frequency measurements

2014 ◽  
Vol 30 ◽  
pp. 1460260
Author(s):  
Michael H. Holzscheiter
Keyword(s):  
Gravitational Field ◽  
Gravitational Force ◽  
Normal Gravity ◽  
Free Fall ◽  
Gravitational Acceleration ◽  
Technical Problems ◽  
Weak Equivalence Principle ◽  
Normal Matter ◽  
Gravitational Experiment ◽  
Fall Experiment

A fundamental question in physics that has yet to be addressed experimentally is whether particles of antimatter, such as the antiproton or positron, obey the weak equivalence principle (WEP). Several theoretical arguments have been put forward arguing limits for possible violations of WEP. No direct `classical' gravitational experiment, the measurement of the free fall of an antiparticle, has been performed to date to determine if a particle of antimatter would experience a force in the gravitational potential of a normal matter body that is different from normal gravity. 30 years ago we proposed a free fall experiment using protons and antiprotons, modeled after the experiment to measure the gravitational acceleration of a free electron. At that time we gave consideration to yet another possible observation of gravitational differences between matter and antimatter based on the gravitational red shift of clocks. I will recall the original arguments and make a number of comments pertaining to the technical problems and other issues that prevented the execution of the antiproton free fall measurement. Note that a different gravitational force on antimatter in the gravitational field of matter would not constitute a violation of CPT, as this is only concerned with the gravitational acceleration of antimatter in the gravitational field of an antimatter body.

THE DEVELOPMENT OF THE GRAVITATIONAL AND YANG–MILLS FIELDS, AND THE TREATMENT OF ACCELERATED FRAMES

2005 ◽  
Vol 20 (32) ◽  
pp. 7485-7504 ◽  
Author(s):  
JONG-PING HSU ◽  
DANA FINE
Keyword(s):  
Quantum Gravity ◽  
Flat Space ◽  
Physical World ◽  
Space Time ◽  
Yang Mills ◽  
Inertial Frames ◽  
Theory Of Gravity ◽  
Mills Field ◽  
Time Transformations ◽  
Accelerated Frames

We discuss ideas and problems regarding classical and quantum gravity, gauge theory of gravity, and space–time transformations between accelerated frames. Both Einstein's theory of gravity and Yang–Mills theory are gauge invariant. The invariance principles are at the very heart of our understanding of the physical world. This paper attempts to survey the development and to reveal problems and limitations of various formulations to gravitational and Yang–Mills fields, and to space–time transformations of accelerated frames. Gravitational force and accelerated frames are two ingredients in Einstein's thought in the period around 1907. Accelerated frames are difficult to define and are not well developed. However, one cannot claim to have a complete understanding of the physical world, if one understands flat space–time physics only from the viewpoint of the special class of inertial frames and ignores the vast class of noninertial frames. The paper highlights three aspects: (1) ideas of gravity as a Yang–Mills field, first discussed by Utiyama; (2) problems of quantum gravity, discussed by Feynman, Dyson and others; (3) space–time properties and the physics of fields and particles in accelerated frames of reference. These unfulfilled aspects of Einstein and Yang–Mills' profound thoughts present a challenge to physicists and mathematicians in the 21st century.

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