For every particle there is a corresponding symmetric particle. Physics has a translational symmetry, which means that the laws and values of physics are the same at every location in the universe. If an observer were to travel from one point to a much farther distant point the observer we see no change in the physics. A broken symmetry introduces change—a non-absolute uniformity. The breaking of symmetries creates complexity in the laws of nature in the outcome of laws. There’s a symmetry and uniformity between the strong and weak nuclear forces, which have been unified as electromagnetism by James Clerk Maxwell. A typical example of vital symmetry breaking is that which gives rise to the balance between matter and antimatter in the early universe. However, there is an asymmetry between the quantum and the large (a la gravity). String theory is the attempt to unify all of physics.
What Does it Mean for Physics to Have Symmetry?
Higgs Boson Calculations Indicate a Finite Lifespan for the Universe
Reblogged from Irene Klotz with Yahoo News.
Scientists are still sorting out the details of last year’s discovery of the Higgs boson particle, but add up the numbers and it’s not looking good for the future of the universe, scientists said Monday [Feb. 18].
“If you use all the physics that we know now and you do what you think is a straightforward calculation, it’s bad news,” Joseph Lykken, a theoretical physicist with the Fermi National Accelerator Laboratory in Batavia, Illinois, told reporters.
Lykeen spoke before presenting his research at the American Association for the Advancement of Science meeting in Boston.
“It may be that the universe we live in is inherently unstable and at some point billions of years from now it’s all going to get wiped out,” said Lykken, who is also on the science team at Europe’s Large Hadron Collider, or LHC, the world’s largest and highest-energy particle accelerator.
The Quantum Universe and the Universal Wave Function
In 1956 Hugh Everett III published his Ph.D. dissertation titled “The Theory of the Universal Wave Function.” In this paper Everett argued for the relative state formulation of quantum theory and a quantum philosophy, which denied wave collapse. Initially, this interpretation was highly criticized by the physics community and when Everett visited Niels Bohr in Copenhagen in 1959 Bohr was unimpressed with Everett’s most recent development (439). In 1957 Everett coined his theory as the Many Worlds Interpretation (MWI) of quantum mechanics. In an attempt to circumvent the problem of defining the mechanism for the state of collapse Everett suggested that all orthogonal relative states are equally valid ontologically. An orthogonal state is one that is mutually exclusive. A system cannot be in two orthogonal states at the same time. As a result of the measurement interaction, the states of the observer have evolved into exclusive states precisely linked to the results of the measurement. At the end of the measurement process the state of the observer is the sum of eigenstate—or a combination of the sums of eigenstates, one sum for each possible value of the eigenvalue. Each sum is the relative state of the observer given the value of the eigenvalue (442-43). What this means is that all-possible states are true and exist simultaneously.
New Paper: The History and Macro-Ontology of the Many Worlds Interpretation of Quantum Physics
In 1956 Hugh Everett III published his Ph.D. dissertation titled “The Theory of the Universal Wave Function.” In this paper Everett argued for the relative state formulation of quantum theory and a quantum philosophy, which denied wave collapse. (DOWNLOAD HERE)
Initially, this interpretation was highly criticized by the physics community and when Everett visited Niels Bohr in Copenhagen in 1959 Bohr was unimpressed with Everett’s most recent development.[1] In 1957 Everett coined his theory as the Many Worlds Interpretation (MWI) of quantum mechanics. In an attempt to circumvent the problem of defining the mechanism for the state of collapse Everett suggested that all orthogonal relative states are equally valid ontologically.[2] What this means is that all-possible states are true and exist simultaneously.
Entangle Schrödinger’s Cat
Nothing is more adorable than a kitten playing with string, but when Schrödinger’s cat becomes entangled, things get really weird.
Two research teams have independently added an extra layer of quantum oddity – the property of entanglement - to a test of wave-particle duality, a real-life demonstration of the ideas captured by physicist Erwin Schrödinger’s famous thought experiment involving a box and a precarious puss.
This extra layer of entanglement lets the researchers delay measuring the results of the test for an indefinite amount of time, even though the measurement itself is supposed to have determined earlier on whether a photon is behaving as a particle or a wave at a particular point in the experiment. It’s the equivalent of putting off the decision to check whether Schrödinger’s cat is alive, dead or something in between, for as long as you like.
Understanding this doubly quantum effect could be useful when building quantum computers and communication networks, which depend on entanglement to function.
Hugh Everett and the Many Worlds Interpretation
In 1956 Hugh Everett III published his Ph.D. dissertation titled “The Theory of the Universal Wave Function.” In this paper Everett argued for the relative state formulation of quantum theory and a quantum philosophy, which denied wave collapse. Initially, this interpretation was highly criticized by the physics community, and when Everett visited Niels Bohr in Copenhagen in 1959 Bohr was unimpressed with Everett’s most recent development [1]. In 1957 Everett coined his theory as the Many Worlds Interpretation (MWI) of quantum mechanics. In an attempt to circumvent the problem of defining the mechanism for the state of collapse Everett suggested that all orthogonal relative states are equally valid ontologically. An orthogonal state is one that is mutually exclusive. A system cannot be in two orthogonal states at the same time. As a result of the measurement interaction, the states of the observer have evolved into exclusive states precisely linked to the results of the measurement. At the end of the measurement process the state of the observer is the sum of eigenstate—or a combination of the sums of eigenstates, one sum for each possible value of the eigenvalue. Each sum is the relative state of the observer given the value of the eigenvalue [2]. What this means is that all-possible states are true and exist simultaneously.
Karl Popper on the Many Worlds Interpretation
In a brief section of Karl Popper’s Quantum Theory and the Schism in Physics[1] he discusses his attraction to the Many Worlds Interpretation of quantum physics as well as the reason for his rejection of it. Popper is actually quite pleased with Everett’s three-fold contribution to the field of quantum physics. Despite his attraction to the interpretation he rejects it based on the falsifiability of the symmetry behind the Schrödinger equation.
Popper’s model allows for a theory to be scientific prior to supported evidence. There is no positive case for purporting a theory under his model. There can only be a negative case to falsify it and as long as it may be potentially falsified it is scientific. Thus, a scientific theory could have no evidence or substantiated facts to provide good reasons for why it may be true. What makes this discussion of MWI interesting is that despite Popper’s attraction to MWI it’s not the attraction that makes it scientific, it’s his criterion of falsification.
In favor of MWI:
- The MWI is completely objective in its discussion of quantum mechanics.
- Everett removes the need and occasion to distinguish between ‘classical’ physical systems, like the measurement apparatus, and quantum mechanical systems, like elementary particles. All systems are quantum (including the universe as a whole).
- Everett shows that the collapse of the state vector, something originally thought to be outside of Schrödinger’s theory, can be shown to arise within the universal [Schrödinger] wave function.
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“The Heisenberg Uncertainty Principle was Never Quite Right”
Pioneering experiments have cast doubt on a founding idea of the branch of physics called quantum mechanics.
The Heisenberg uncertainty principle is in part an embodiment of the idea that in the quantum world, the mere act of observing an event changes it.
But the idea had never been put to the test, and a team writing in Physical Review Letters says “weak measurements” prove the rule was never quite right.
That could play havoc with “uncrackable codes” of quantum cryptography.
Quantum mechanics has since its very inception raised a great many philosophical and metaphysical debates about the nature of nature itself.
The experiment requires preparing pairs of “entangled” photons, the particles from which light is made (BBC)
Hugh Everett’s Dissertation: “The Many Worlds Interpretation of Quantum Mechanics”
In 1956 Hugh Everett III published his Ph.D. dissertation titled “The Theory of the Universal Wave Function.” In this paper Everett argued for the relative state formulation of quantum theory and a quantum philosophy, which denied wave collapse. Initially, this interpretation was highly criticized by the physics community and when Everett visited Niels Bohr in Copenhagen in 1959. Bohr was unimpressed with Everett’s most recent development.[1]
In 1957 Everett coined his theory as the Many Worlds Interpretation of quantum mechanics. In an attempt to circumvent the problem of defining the mechanism for the state of collapse, Everett suggested that all orthogonal relative states are equally valid ontologically.[2] What this means is that all possible states are true and exist simultaneously.
We have a problem of using secondary sources. I’ve provided a link below that takes you back to Everett’s original dissertation to read for ourselves.
Word of the Week Wednesday: Flavor (Particle Physics)
Word of the Week: Flavor (particle physics)
Definition: The property that makes the distinction between one quark and anthers. Quarks come in six flavors: up, down, strange, charm, top, and bottom.
More about the term: The term is sometimes extended to describe different flavors of a lepton; in that case, the varieties are electron, electron neutrino, muon, muon neutrino, tau, and tau neutrino. For more about the term and related information please see John Gribbin’s Q is for Quantum (London: Weidenfeld & Nicholson, 1998), 141.