# phys: apropos of transitions, even a tiny wobble may reshape theoretical views of the universe

<< The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. >>️

<< Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision. >>

<< The first result from the Muon g-2 experiment at Fermilab confirms the result from the experiment performed at Brookhaven National Lab two decades ago. Together, the two results show strong evidence that muons diverge from the Standard Model prediction. >>

<< The accepted theoretical values for the muon are:

g-factor: 2.00233183620(86)

anomalous magnetic moment: 0.00116591810(43)

[uncertainty in parentheses]

The new experimental world-average results announced by the Muon g-2 collaboration today are:

g-factor: 2.00233184122(82)

anomalous magnetic moment: 0.00116592061(41)

The combined results from Fermilab and Brookhaven show a difference with theory at a significance of 4.2 sigma, a little shy of the 5 sigma (or standard deviations) that scientists require to claim a discovery but still compelling evidence of new physics. The chance that the results are a statistical fluctuation is about 1 in 40,000. >>️

We’re thrilled to announce that the first results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics! #gminus2

https://t.co/tUx4ojzIps https://t.co/t1ufui2Mwu   

17:01  Apr 7,  2021

https://twitter.com/Fermilab/status/1379811596755681286

Tracy Marc. First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics. Apr 7, 2021.

https://news.fnal.gov/2021/04/first-results-from-fermilabs-muon-g-2-experiment-strengthen-evidence-of-new-physics

Also

Themis Bowcock, Mark Lancaster. How we found hints of new particles or forces of nature – and why it could change physics. Apr 8, 2021.

 

https://theconversation.com/how-we-found-hints-of-new-particles-or-forces-of-nature-and-why-it-could-change-physics-158564

B. Abi et al. (Muon g−2  Collaboration)

 Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm. Phys. Rev. Lett. 126, 141801. Apr 7, 2021.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.141801

A primer in particle physics:

Jonathan Carroll. Explainer: Standard Model of Particle Physics. Aug 25, 2011.

https://theconversation.com/explainer-standard-model-of-particle-physics-2539

a 'cartouche' of the Standard Model 

https://images.theconversation.com/files/2516/original/sml_small.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1055&fit=crop&dpr=3

# phys: trace the birth and evolution of a quasiparticle entity

<< The idea of quasiparticles was first introduced in the 1930s by physicist Lev Landau, who was trying to gain a better understanding of complex quantum systems. >>

<< Over the past decades, physicists worldwide have been trying to gain a better understanding of non-equilibrium dynamics in quantum many-body systems. Some studies investigated what are known as quasiparticles, disturbances or entities in physical systems that exhibit behavior similar to that of particles. >>

In this study AA << observed three distinct regimes of impurity evolution marked by dynamic transitions. These regimes then link initial few-body and later many-body physical dynamics. >>

Ingrid Fadelli. Observing the birth of a quasiparticle. Mar 11, 2021.

https://phys.org/news/2021-03-birth-quasiparticle.html

<<  These results offer a systematic picture of polaron formation from weak to strong impurity interactions. They reveal three distinct regimes of evolution with dynamical transitions that provide a link between few-body processes and many-body dynamics. Our measurements reveal universal dynamical behaviour in interacting many-body systems and demonstrate new pathways to study non-equilibrium quantum phenomena. >>

Magnus G. Skou, Thomas G. Skov, et al. Non-equilibrium quantum dynamics and formation of the Bose polaron. 

Nat. Phys. (2021). doi: 10.1038/ s41567-021-01184-5. Feb 25, 2021.

https://www.nature.com/articles/s41567-021-01184-5

"three distinct regimes"  

https://www.nature.com/articles/s41567-021-01184-5.epdf?no_publisher_access=1&r3_referer=nature

# gst: vacuum fluctuations (even in complete darkness)

<< physics is increasingly discovering how our universe is shaped by fluctuations of physical fields, which not only lead to tiny shifts of spectral lines of atoms, but moreover may cause the evaporation of black holes, and are ultimately responsible for the large-scale structure of our universe,  >>

AA  << have now made a large leap toward controlling strongly enhanced vacuum fluctuations much faster than typical timescales of virtual photons. To this end, they created a specialized semiconductor structure in which electrons are extremely strongly coupled to the light fields of tiny antennas designed for the so-called terahertz spectral range. As a result, vacuum fluctuations of light and matter fields participate in the interaction, strongly increasing the presence of virtual photons—even in complete darkness. >>

Understanding vacuum fluctuations in space. University of Regensburg. Aug 10, 2020.

https://phys.org/news/2020-08-vacuum-fluctuations-space.html 

<< The abrupt modification of the vacuum ground state causes spectrally broadband polarization oscillations confirmed by (AA) quantum model. In the future, this subcycle shaping of hybrid quantum states may trigger cavity-induced quantum chemistry, vacuum-modified transport or cavity-controlled superconductivity, opening new scenarios >>

M. Halbhuber, J. Mornhinweg, et al. Non-adiabatic stripping of a cavity field from electrons in the deep-strong coupling regime. Nat. Photonics. doi: 10.1038/ s41566-020-0673-2. Aug 10, 2020.

https://www.nature.com/articles/s41566-020-0673-2

# physics: SQUID, a probe at the boundary between 'quantum' and 'classic' worlds

<< A new device that relies on flowing clouds of ultracold atoms promises potential tests of the intersection between the weirdness of the quantum world and the familiarity of the macroscopic world we experience every day. The atomtronic Superconducting QUantum Interference Device (SQUID) is also potentially useful for ultrasensitive rotation measurements and as a component in quantum computers. >>

AA << created the device by trapping cold atoms in a sheet of laser light. A second laser intersecting the sheet "painted" patterns that guided the atoms into two semicircles separated by small gaps known as Josephson Junctions. When the SQUID is rotated and the Josephson Junctions are moved toward each other, the populations of atoms in the semicircles change as a result of quantum mechanical interference of currents through Josephson Junctions. By counting the atoms in each section of the semicircle, the researchers can very precisely determine the rate the system is rotating.>>

James Riordon. Atomtronic device could probe boundary between quantum, everyday worlds. Los Alamos National Laboratory. July 17, 2020.

https://phys.org/news/2020-07-atomtronic-device-probe-boundary-quantum.html

C. Ryu, E. C. Samson, M. G. Boshier. Quantum interference of currents in an atomtronic SQUID. Nat Commun 11, 3338. doi: 10.1038/ s41467-020-17185-6. Jul 3, 2020.

https://www.nature.com/articles/s41467-020-17185-6

# phys: nature does not always respect symmetry, the hypothesis

<< Physicists have been looking for laws that explain both the microscopic world of elementary particles and the macroscopic world of the universe and the Big Bang at its beginning, expecting that such fundamental laws should have symmetry in all circumstances. However, last year, two physicists found a theoretical proof that, at the most fundamental level, nature does not respect symmetry. >>

<< To try to understand gravity on the quantum level, Hirosi Ooguri, (..) and Daniel Harlow, (..) started with the holographic principle. This principle explains three-dimensional phenomena influenced by gravity on a two-dimensional flat space that is not influenced by gravity.  >>

<< The researchers showed that symmetry only affects the shaded regions in the diagram, not around the spot in the middle, thus there cannot be global symmetry.  >>

Motoko Kakubayashi. Gravity: We might have been getting it wrong this whole time. Kavli Institute for the Physics and Mathematics of the Universe. Jan 24, 2020.

https://m.phys.org/news/2020-01-gravity-wrong.html

Daniel Harlow, Hirosi Ooguri. Constraints on Symmetries from Holography. Phys. Rev. Lett. 122, 191601. doi: 10.1103/ PhysRevLett.122.191601. May 17, 2019.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.191601

Daniel Harlow, Hirosi Ooguri. Symmetries in quantum field theory and quantum gravity. arXiv: 1810.05338v2 [hep-th]. Jun 6, 2019.

https://arxiv.org/abs/1810.05338

# phys: the qu-wave of the natural antibiotic gramicidin

<< One of the great counterintuitive puzzles of quantum mechanics is wave-particle duality. This is the phenomenon in which objects behave both like particles and like waves. >>

AA << for the first time, have demonstrated quantum interference in molecules of gramicidin, a natural antibiotic made up of 15 amino acids. Their work paves the way for the study of the quantum properties of  biomolecules and sets the scene for experiments that exploit the quantum nature of enzymes, DNA, and perhaps one day simple life forms such as viruses. >>

A natural biomolecule has been measured acting like a quantum wave for the first time. Mit Tech Rew - Emerging Technology from the arXiv. Nov 9, 2019. 

https://www.technologyreview.com/s/614688/a-natural-biomolecule-has-been-measured-acting-in-a-quantum-wave-for-the-first-time/

Armin Shayeghi, Philipp Rieser, et al. Matter-wave interference of a native polypeptide. arXiv:1910.14538v1 [quant-ph]. Oct 31, 2019.

https://arxiv.org/abs/1910.14538

Also

keyword "quantum" in FonT

https://flashontrack.blogspot.com/search?q=quantum