Quantum gravity

2019 ◽  
Vol 32 (3) ◽  
pp. 318-322
Author(s):  
Elia A. Sinaiko
Keyword(s):  
Quantum Mechanics ◽  
Particle Physics ◽  
Nuclear Force ◽  
Curve Space ◽  
Short Paper ◽  
Spatial Properties ◽  
Straight Line ◽  
Thing In Itself ◽  
Surrounding Space ◽  
Fundamental Forces

Gravity has been shown in theories of relativity to be the curving of space around massive bodies. Thus, objects in orbits are following a straight line along a curved space. Why massive bodies curve space is not explained. We continue to ask “What is Gravity?” Quantum mechanics unites theories of electro-magnetism (QED), the weak nuclear force (EWT), and the strong nuclear force (QCD) in the standard model of particle physics, or with a grand unified theory (GUT) sought for these three fundamental forces. As yet there is no empirically verified quantum theory of gravity unified with these three fundamental forces. Considering gravity to be the curving of space, it is evident that gravity supervenes from the properties of space itself. In this short paper, we will attempt to define one of these spatial properties. We will not attempt to define the properties of time, though time appears to be a part of a complete model of gravity. At least in this regard, and likely in many others, our model will be incomplete. We will build a case for the massive collapse of probability density waves (PDWs) in surrounding space, due to the interactions of particles in massive bodies. The collapse of these probabilities, of each particle’s possible superposition somewhere in the surrounding space, causes the apparent “curving” of space. We will conclude that space is not the absence of things. Space is a thing in itself. Included in the properties of space is the potential to contain/transmit PDWs. This potential is suggested by both the theories of relativity and the experimental observations of quantum mechanics. In the presence of massive bodies, particle superposition and the probability of existence in the surrounding space is, to varying degrees, lost and space appears to curve as a consequence.

Q & A. Lisa Randall. [interview]

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
New York ◽  
New York City ◽  
Particle Physics ◽  
Harvard University ◽  
The Past ◽  
Talent Search ◽  
Cosmological Inflation ◽  
On Line ◽  
Theoretical Physicist ◽  
Fundamental Forces

Lisa Randall is a theoretical physicist working in particle physics and cosmology. She was born in Queens, New York City, on June 18, 1962. Lisa Randall is an alumna of Hampshire College Summer Studies in Mathematics; and she graduated from Stuyvesant High School in 1980. She won first place in the 1980 Westinghouse Science Talent Search at the age of 18; and at Harvard University, Lisa Randall earned both a BA in physics (1983) and a PhD in theoretical particle physics (1987) under advisor Howard Mason Georgi III, a theoretical physicist. She is currently Frank B. Baird, Jr. Professor of Science on the physics faculty of Harvard University, where he has been for the past a decade. Her works concerns elementary particles and fundamental forces, and has involved the study of a wide variety of models, the most recent involving dimensions. She has also worked on supersymmetry, Standard Model observables, cosmological inflation, baryogenesis, grand unified theories, and general relativity. Consequently, her studies have made her among the most cited and influential theoretical physicists and she has received numerous awards and honors for her scientific endeavors. Since December 27, 2010 at 00:42 (GMT+7), Lisa Randall is Twitter’s user with account @lirarandall. “Thanks to new followers. Interesting how different it feels broadcasting on line vs.via book or article. Explanations? Pithiness? Rapidity?” is her first tweet.

The Physical World

2017 ◽  
Author(s):  
Nicholas Manton ◽  
Nicholas Mee
Keyword(s):  
Quantum Mechanics ◽  
Particle Physics ◽  
Variational Principles ◽  
Black Body ◽  
Black Body Radiation ◽  
Physical World ◽  
Atomic Scale ◽  
Solid State Physics ◽  
Least Action ◽  
Dimensional Spacetime

The book is an inspirational survey of fundamental physics, emphasizing the use of variational principles. Chapter 1 presents introductory ideas, including the principle of least action, vectors and partial differentiation. Chapter 2 covers Newtonian dynamics and the motion of mutually gravitating bodies. Chapter 3 is about electromagnetic fields as described by Maxwell’s equations. Chapter 4 is about special relativity, which unifies space and time into 4-dimensional spacetime. Chapter 5 introduces the mathematics of curved space, leading to Chapter 6 covering general relativity and its remarkable consequences, such as the existence of black holes. Chapters 7 and 8 present quantum mechanics, essential for understanding atomic-scale phenomena. Chapter 9 uses quantum mechanics to explain the fundamental principles of chemistry and solid state physics. Chapter 10 is about thermodynamics, which is built around the concepts of temperature and entropy. Various applications are discussed, including the analysis of black body radiation that led to the quantum revolution. Chapter 11 surveys the atomic nucleus, its properties and applications. Chapter 12 explores particle physics, the Standard Model and the Higgs mechanism, with a short introduction to quantum field theory. Chapter 13 is about the structure and evolution of stars and brings together material from many of the earlier chapters. Chapter 14 on cosmology describes the structure and evolution of the universe as a whole. Finally, Chapter 15 discusses remaining problems at the frontiers of physics, such as the interpretation of quantum mechanics, and the ultimate nature of particles. Some speculative ideas are explored, such as supersymmetry, solitons and string theory.

Quantum 20/20

2019 ◽  
Author(s):  
Ian R. Kenyon
Keyword(s):  
Quantum Mechanics ◽  
Hall Effect ◽  
Particle Physics ◽  
Quantum Spin ◽  
Lessons Learned ◽  
Compact Stars ◽  
Einstein Condensation ◽  
Local Conservation ◽  
Variable Theory ◽  
Quantum Gauge Theory

This text reviews fundametals and incorporates key themes of quantum physics. One theme contrasts boson condensation and fermion exclusivity. Bose–Einstein condensation is basic to superconductivity, superfluidity and gaseous BEC. Fermion exclusivity leads to compact stars and to atomic structure, and thence to the band structure of metals and semiconductors with applications in material science, modern optics and electronics. A second theme is that a wavefunction at a point, and in particular its phase is unique (ignoring a global phase change). If there are symmetries, conservation laws follow and quantum states which are eigenfunctions of the conserved quantities. By contrast with no particular symmetry topological effects occur such as the Bohm–Aharonov effect: also stable vortex formation in superfluids, superconductors and BEC, all these having quantized circulation of some sort. The quantum Hall effect and quantum spin Hall effect are ab initio topological. A third theme is entanglement: a feature that distinguishes the quantum world from the classical world. This property led Einstein, Podolsky and Rosen to the view that quantum mechanics is an incomplete physical theory. Bell proposed the way that any underlying local hidden variable theory could be, and was experimentally rejected. Powerful tools in quantum optics, including near-term secure communications, rely on entanglement. It was exploited in the the measurement of CP violation in the decay of beauty mesons. A fourth theme is the limitations on measurement precision set by quantum mechanics. These can be circumvented by quantum non-demolition techniques and by squeezing phase space so that the uncertainty is moved to a variable conjugate to that being measured. The boundaries of precision are explored in the measurement of g-2 for the electron, and in the detection of gravitational waves by LIGO; the latter achievement has opened a new window on the Universe. The fifth and last theme is quantum field theory. This is based on local conservation of charges. It reaches its most impressive form in the quantum gauge theories of the strong, electromagnetic and weak interactions, culminating in the discovery of the Higgs. Where particle physics has particles condensed matter has a galaxy of pseudoparticles that exist only in matter and are always in some sense special to particular states of matter. Emergent phenomena in matter are successfully modelled and analysed using quasiparticles and quantum theory. Lessons learned in that way on spontaneous symmetry breaking in superconductivity were the key to constructing a consistent quantum gauge theory of electroweak processes in particle physics.

scholarly journals On The Bosons’ Range of the Weak Interaction

2018 ◽  
Vol 14 (3) ◽  
pp. 5865-5868
Author(s):  
Antonio Puccini
Keyword(s):  
Quantum Mechanics ◽  
Weak Interaction ◽  
Uncertainty Principle ◽  
Nuclear Force ◽  
Massive Particle ◽  
Maximum Distance ◽  
Gauge Bosons ◽  
Binding Condition ◽  
Upper Limit

As known the Weak Nuclear Force or Weak Interaction(WI) acts between quarks (Qs) and leptons. The action of the WI is mediated by highly massive gauge bosons. How does a nuclear Q emit such a massive particle, approximately 16000 or 40000 times its mass? Who provides so much energy to a up Q or a down Q? However, it must be considered that according to Quantum Mechanics it is possible to loan temporarily some energy, but to a precise and binding condition, established by the Uncertainty Principle: the higher the energy borrowed, the shorter the duration of the loan. Our calculations show that the maximum distance these bosons can travel, i.e. the upper limit of their range, corresponds to 1.543×10-15 [cm] for particles W+ and W- and 1.36×10-15[cm] for Z° particles.

Quantum Many-Particle Systems and Second Quantization

2019 ◽  
pp. 5-44
Author(s):  
Hans-Peter Eckle
Keyword(s):  
Quantum Mechanics ◽  
Particle Physics ◽  
Mathematical Formulation ◽  
Particle Systems ◽  
Quantum Field ◽  
Second Quantization ◽  
Creation And Annihilation Operators ◽  
Quantum Matter ◽  
Interacting Systems ◽  
The Many

Chapter 2 provides a review of pertinent aspects of the quantum mechanics of systems composed of many particles. It focuses on the foundations of quantum many-particle physics, the many-particle Hilbert spaces to describe large assemblies of interacting systems composed of Bosons or Fermions, which lead to the versatile formalism of second quantization as a convenient and eminently practical language ubiquitous in the mathematical formulation of the theory of many-particle systems of quantum matter. The main objects in which the formalism of second quantization is expressed are the Bosonic or Fermionic creation and annihilation operators that become, in the position basis, the quantum field operators.

scholarly journals Precision Measurement of the Position-Space Wave Functions of Gravitationally Bound Ultracold Neutrons

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Y. Kamiya ◽  
G. Ichikawa ◽  
S. Komamiya
Keyword(s):  
Quantum Mechanics ◽  
Particle Physics ◽  
Bound States ◽  
Wave Functions ◽  
Recent Measurement ◽  
Ultracold Neutrons ◽  
Neutron Guide ◽  
Position Space ◽  
Position Sensitive Detectors ◽  
Space Wave

Gravity is the most familiar force at our natural length scale. However, it is still exotic from the view point of particle physics. The first experimental study of quantum effects under gravity was performed using a cold neutron beam in 1975. Following this, an investigation of gravitationally bound quantum states using ultracold neutrons was started in 2002. This quantum bound system is now well understood, and one can use it as a tunable tool to probe gravity. In this paper, we review a recent measurement of position-space wave functions of such gravitationally bound states and discuss issues related to this analysis, such as neutron loss models in a thin neutron guide, the formulation of phase space quantum mechanics, and UCN position sensitive detectors. The quantum modulation of neutron bound states measured in this experiment shows good agreement with the prediction from quantum mechanics.

scholarly journals Theory of Discrete Gravity

2018 ◽  
Author(s):  
Mihir Kumar Jha
Keyword(s):  
General Relativity ◽  
Quantum Mechanics ◽  
Loop Quantum Gravity ◽  
Riemannian Metric ◽  
Space Time ◽  
Final Theory ◽  
Theory Of Everything ◽  
Single Field ◽  
Fundamental Forces ◽  
New Framework

Theory of everything (T.O.E), final theory or ultimate theory is a theoretical framework in the field of physics, which holds an ultimate key to unify all the fundamental forces of nature in a single field. In other words such theory can glue quantum mechanics with general relativity into a single framework. Many theories have been postulated over the decades but the dominant one includes string theory and loop quantum gravity. In this paper I would like to present a new framework which can unify quantum mechanics with general relativity by showing that the change in Riemannian metric or the bend in space time is always an integral multiple of planks constant and since gravity is the result due to bend in space-time, gravity itself is a discrete force

scholarly journals From the 3D Constructions of Gell-Mann’s 1960 to the Higgs Field Constructions with Data of all Elementary Particles

2021 ◽  
Vol 3 (4) ◽  
pp. 25-31
Author(s):  
Hermann Josef Scheuber
Keyword(s):  
Quantum Mechanics ◽  
New Media ◽  
Particle Physics ◽  
Higgs Field ◽  
Elementary Particles ◽  
The Real ◽  
Charge Axis

In 1960 Gell-Mann completed the “Particle Zoo” with pseudo 3D constructions: a Spin-Strangeness plane and an oblique incident charge. In this way he investigated with the crossing Kaon connections (1/2 Spin, -1, 0, 1 Strangeness, -1, 0, 1 Charge) 3 quark-points with simple proper fractions. With the new media the construction can be better detected with a perpendicular charge axis as could be done with the GeoGebra 5 program. But 1960 the Quantum Mechanics didn’t want the Strangeness and prevented a construction for everyman. Only experts were mathematically according to Lagrange allowed to get an idea about the real matter. But according to the Euclid Geometry 3 points lay on a circle line; if twice, then with 6 exact Quark points all other known requirements of the particle physics can be done by construction.

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