Physics News and Discussions

weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

The first experimental observation of subpicosecond electron bunches originating from an ultracold source
https://phys.org/news/2023-05-experimen ... acold.html
by Ingrid Fadelli , Phys.org
Identifying new sources that produce electrons faster could help to advance the many imaging techniques that rely on electrons. In a recent paper published in Physical Review Letters, a team of researchers at Eindhoven University of Technology demonstrated the scattering of subpicosecond electron bunches from an ultracold electron source.

"Our research group is working to develop the next generation of ultrafast electron sources to push imaging techniques such as ultrafast electron diffraction to the next level," Tim de Raadt, one of the researchers who carried out the study, told Phys.org.

"The idea of using laser-cooled ultracold gas clouds as an electron source to improve the state-of-the-art in brightness was first introduced in a paper published in 2005. Since then, research efforts have produced multiple versions of such a ultracold electron source, with the most recent one (used in this work) focusing on making the source compact, easy to align and operate, and being more stable, as described in another past paper that also studied the transverse electron beam properties."

The primary objective of the recent work by de Raadt and his colleagues was to further assess the performance of the type of compact laser cooled ultracold source identified in their previous work, particularly looking at its longitudinal beam properties. By better understanding the physics behind this source, they could optimize its performance and enable its use to advance imaging techniques.
weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

Experiments see first evidence of a rare Higgs boson decay
https://phys.org/news/2023-05-evidence- ... decay.html
by CERN

The discovery of the Higgs boson at CERN's Large Hadron Collider (LHC) in 2012 marked a significant milestone in particle physics. Since then, the ATLAS and CMS collaborations have been diligently investigating the properties of this unique particle and searching to establish the different ways in which it is produced and decays into other particles.

At the Large Hadron Collider Physics (LHCP) conference this week, ATLAS and CMS report how they teamed up to find the first evidence of the rare process in which the Higgs boson decays into a Z boson, the electrically neutral carrier of the weak force, and a photon, the carrier of the electromagnetic force. This Higgs boson decay could provide indirect evidence of the existence of particles beyond those predicted by the Standard Model of particle physics.

The decay of the Higgs boson into a Z boson and a photon is similar to that of a decay into two photons. In these processes, the Higgs boson does not decay directly into these pairs of particles. Instead, the decays proceed via an intermediate "loop" of "virtual" particles that pop in and out of existence and cannot be directly detected. These virtual particles could include new, as yet undiscovered particles that interact with the Higgs boson.

The Standard Model predicts that, if the Higgs boson has a mass of around 125 billion electronvolts, approximately 0.15% of Higgs bosons will decay into a Z boson and a photon. But some theories that extend the Standard Model predict a different decay rate. Measuring the decay rate therefore provides valuable insights into both physics beyond the Standard Model and the nature of the Higgs boson.

Previously, using data from proton–proton collisions at the LHC, ATLAS and CMS independently conducted extensive searches for the decay of the Higgs boson into a Z boson and a photon. Both searches used similar strategies, identifying the Z boson through its decays into pairs of electrons or muons—heavier versions of electrons. These Z boson decays occur in about 6.6% of the cases.

In these searches, collision events associated with this Higgs boson decay (the signal) would be identified as a narrow peak, over a smooth background of events, in the distribution of the combined mass of the decay products. To enhance the sensitivity to the decay, ATLAS and CMS exploited the most frequent modes in which the Higgs boson is produced and categorized events based on the characteristics of these production processes. They also used advanced machine-learning techniques to further distinguish between signal and background events.
User avatar
caltrek
Posts: 6509
Joined: Mon May 17, 2021 1:17 pm

Re: Physics News and Discussions

Post by caltrek »

First Signs of Rare Higgs Boson Decay Discovered by Physicists
by Mike McCrae
May 29, 2023

Introduction:
(Science Alert)A refined hunt for the extremely rare transformation of the Higgs boson has delivered results, providing the first evidence of a process that could hint at unknown particles.

Reconciling the results of several years' worth of proton crashes inside two different detectors at the European Organization for Nuclear Research's (CERN) Large Hadron Collider (LHC), physicists bumped up the statistical precision of the rate at which the famous 'mass-giving' particle decayed into a photon and a Z boson. (See also previous article in this thread -caltrek)

The results, shared at the LHC Physics Conference in Belgrade last week, fall well short of what might be considered significant. But the process itself can be improved to hone in on the bubble and hiss of quantum recipes, and help determine where exotic new forces and building blocks might exist.

The Higgs particle became the darling of the physics world in 2012 when evidence of its existence was confirmed by the ATLAS (or 'A Toroidal LHC Apparatus') and CMS (Compact Muon Solenoid) detectors at CERN.

Not only was it the final entry in that grand map of particles – the Standard Model – to be experimentally confirmed; its observation promised to be a window into hidden parts of the quantum realm.

After a further brief review of the nature of Higgs particle, the article explains how it is hoped that continued effort will yield the discovery of new particles.

Read more here: https://www.sciencealert.com/first-sig ... ysicists
Don't mourn, organize.

-Joe Hill
User avatar
wjfox
Site Admin
Posts: 8733
Joined: Sat May 15, 2021 6:09 pm
Location: London, UK
Contact:

Re: Physics News and Discussions

Post by wjfox »

Qubits 30 meters apart used to confirm Einstein was wrong about quantum

Experiment linked qubits using a supercold wire over 30 meters long.

JOHN TIMMER - 5/10/2023, 7:12 PM

A new experiment uses superconducting qubits to demonstrate that quantum mechanics violates what's called local realism by allowing two objects to behave as a single quantum system no matter how large the separation between them. The experiment wasn't the first to show that local realism isn't how the Universe works—it's not even the first to do so with qubits.

But it's the first to separate the qubits by enough distance to ensure that light isn't fast enough to travel between them while measurements are made. And it did so by cooling a 30-meter-long aluminum wire to just a few milliKelvin. Because the qubits are so easy to control, the experiment provides a new precision to these sorts of measurements. And the hardware setup may be essential for future quantum computing efforts.

Albert Einstein was famously uneasy with some of the consequences of quantum entanglement. If quantum mechanics were right, then a pair of entangled objects would behave as a single quantum system no matter how far apart the objects were. Altering the state of one of them should instantly alter the state of the second, with the change seemingly occurring faster than light could possibly travel between the two objects. This, Einstein argued, almost certainly had to be wrong.

https://arstechnica.com/science/2023/05 ... ity-local/


Image
Credit: ETH Zurich / Daniel Winkler
weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

Quantum materials: Electron spin measured for the first time
https://phys.org/news/2023-06-quantum-m ... ctron.html
by Università di Bologna

An international research team has succeeded for the first time in measuring the electron spin in matter—i.e., the curvature of space in which electrons live and move—within "kagome materials," a new class of quantum materials.

The results obtained—published in Nature Physics—could revolutionize the way quantum materials are studied in the future, opening the door to new developments in quantum technologies, with possible applications in a variety of technological fields, from renewable energy to biomedicine, from electronics to quantum computers.

Success was achieved by an international collaboration of scientists, in which Domenico Di Sante, professor at the Department of Physics and Astronomy "Augusto Righi," participated for the University of Bologna as part of his Marie Curie BITMAP research project. He was joined by colleagues from CNR-IOM Trieste, Ca' Foscari University of Venice, University of Milan, University of Würzburg (Germany), University of St. Andrews (UK), Boston College and University of Santa Barbara (U.S.).
weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

Large Hadron Collider may be closing in on the universe's missing antimatter
By Keith Cooper published about 18 hours ago
'Through more precise measurements, large improvements have been made in our knowledge.'


Physicists at the Large Hadron Collider (LHC) are closing in on an explanation for why we live in a universe of matter and not antimatter.

Matter and antimatter are two sides of the same coin. Every type of particle has an anti-particle, which is its equal and opposite. For instance, the antimatter equivalent of a negatively charged electron is a positively charged positron.

The Standard Model of physics tells us that if we substitute a particle for its antiparticle, it should still operate within the laws of physics in the same way. As such, the Big Bang should not have had a preference for creating one type over another — this symmetry at the heart of nature means that matter and antimatter should have formed in equal amounts in the Big Bang.

Lucky for us, this does not seem to have been the case, because when you put matter and antimatter together, the outcome is explosive to say the least. Had matter and antimatter been crafted in equal amounts, then they would have annihilated each other, creating a cosmos filled with a sea of radiation, no atoms and no life. Today, the only antimatter is that which is produced in particle decays and interactions.
More:
https://www.space.com/large-hadron-coll ... tification
User avatar
wjfox
Site Admin
Posts: 8733
Joined: Sat May 15, 2021 6:09 pm
Location: London, UK
Contact:

Re: Physics News and Discussions

Post by wjfox »

Camera brings ‘unprecedented clarity’ to restoration of historic artworks

Mon 26 Jun 2023 08.02 BST

Scientists have developed technology that will revolutionise the restoration of historic works of art by allowing conservators to identify and remove ageing varnish with total accuracy.

A team at King’s College London’s department of physics has harnessed the power of fluorescence to bring “unprecedented clarity” to the conservation process, said Prof Klaus Suhling.

A revolutionary camera will allow experts to distinguish between varnish and other components in an artwork, such as paints and binders.

[...]

The King’s College team developed a 25,000-pixel photon sensitive camera that uses a technique called macroscopic fluorescence lifetime imaging (FLIM) to harness the natural fluorescence in centuries-old varnish.

Each pixel has a stopwatch that measures when the light from a surface enters it. “By comparing the fluorescence of the varnish to these other components, we can chart where varnish sits with a level of accuracy never previously achieved,” said Suhling.

https://www.theguardian.com/artanddesig ... c-artworks


Image
Credit: National Trust Images/National Trust
weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

Researchers devise new quantum photonics technique to create better holograms
https://phys.org/news/2023-07-quantum-p ... grams.html
by University of Ottawa
By enabling the recording and reconstruction of faint light beams containing a single particle of light, a new technique opens the door to holographic imaging of remote objects.

Researchers from the University of Ottawa, the National Research Council of Canada(NRC) and Imperial College London have developed a new quantum-inspired technique to perform holography, the rendering of a three-dimensional image using lasers— just like in Star Trek and Star Wars.

Led byuOttawa's Dr. Benjamin Sussman, adjunct professor of physics in the Faculty of Science, the researchers collaborated at the uOttawa-NRC Joint Centre for Extreme Photonics to develop a pioneering quantum-inspired technique for holography. Their aim was to record and reconstruct extremely faint light beams, consisting of a mere single particle of light, known as a photon.

Their work has the potential to revolutionize 3D scene reconstruction and unlock a plethora of applications across diverse fields.
weatheriscool
Posts: 12973
Joined: Sun May 16, 2021 6:16 pm

Re: Physics News and Discussions

Post by weatheriscool »

Einstein's theory of relativity reaffirmed, despite doubts from quantum physicists
https://phys.org/news/2023-07-einstein- ... cists.html
by Leibniz University Hannover

One of the most basic assumptions of fundamental physics is that the different properties of mass—weight, inertia and gravitation—always remain the same in relation to each other. Without this equivalence, Einstein's theory of relativity would be contradicted and our current physics textbooks would have to be rewritten. Although all measurements to date confirm the equivalence principle, quantum theory postulates that there should be a violation.

This inconsistency between Einstein's gravitational theory and modern quantum theory is the reason why ever more precise tests of the equivalence principle are particularly important. A team from the Center of Applied Space Technology and Microgravity (ZARM) at University of Bremen, in collaboration with the Institute of Geodesy (IfE) at Leibniz University Hannover, has now succeeded in proving with 100 times greater accuracy that passive gravitational mass and active gravitational mass are always equivalent—regardless of the particular composition of the respective masses.

The research was conducted within the framework of the Cluster of Excellence "QuantumFrontiers." Today, the team published their findings as a highlights article in Physical Review Letters.
User avatar
caltrek
Posts: 6509
Joined: Mon May 17, 2021 1:17 pm

Re: Physics News and Discussions

Post by caltrek »

New Synthetic Particles Move Like Hurricanes and Algae
by James Devitt
July 17, 2023

Introduction:
(Futurity) A new system uses laser beams and the spinning of microscopic rotors to replicate the movement of naturally occurring phenomena, such as hurricanes and algae.

The breakthrough, reported in the journal Nature Communications, reveals new ways that living matter can be reproduced on a cellular scale.

“Living organisms are made of materials that actively pump energy through their molecules, which produce a range of movements on a larger cellular scale,” explains Matan Yah Ben Zion, a doctoral student in New York University’s physics department at the time of the work and one of the paper’s authors. “By engineering cellular-scale machines from the ground up, our work can offer new insights into the complexity of the natural world.”
The research centers on vortical flows, which appear in both biological and meteorological systems, such as algae or hurricanes. Specifically, particles move into orbital motion in the flow generated by their own rotation, resulting in a range of complex interactions.

To better understand these dynamics, the paper’s authors, who also include Alvin Modin, an NYU undergraduate at the time of the study and now a doctoral student at Johns Hopkins University, and Paul Chaikin, an NYU physics professor, sought to replicate them at their most basic level. To do so, they created tiny micro-rotors—about 1/10th the width of a strand of human hair—to move micro-particles using a laser beam (Chaikin and his colleagues devised this process in a previous work).

The researchers found that the rotating particles mutually affected each other into orbital motion, with striking similarities to dynamics observed by other scientists in “dancing” algae—algae groupings that move in concert with each other.
Read more here: https://www.futurity.org/vortical-flow ... 944402-2
Don't mourn, organize.

-Joe Hill
Post Reply