Jan 8, 2025 08:24 PM
Scientists find 'spooky' quantum entanglement on incredibly tiny scales — within individual protons
https://www.space.com/spooky-action-smal...rks-gluons
EXCERPTS: . . . "Before we did this work, no one had looked at entanglement inside of a proton in experimental high-energy collision data,” team member and Brookhaven Lab physicist Zhoudunming Tu said in a statement. "For decades, we’ve had a traditional view of the proton as a collection of quarks and gluons, and we’ve been focused on understanding so-called single-particle properties, including how quarks and gluons are distributed inside the proton.
"Now, with evidence that quarks and gluons are entangled, this picture has changed. We have a much more complicated, dynamic system."
The team's research, the culmination of six years of work, refines scientists' understanding of how entanglement influences the structure of protons.
[...] Comparing HERA data with the entropy calculations, the team's results matched their predictions perfectly, providing strong evidence that quarks and gluons inside protons are maximally entangled.
"Entanglement doesn't only happen between two particles but among all the particles," Kharzeev said. "Maximal entanglement inside the proton emerges as a consequence of strong interactions that produce a large number of quark-antiquark pairs and gluons."
The revelation of maximal entanglement of quarks and gluons within protons could help reveal what keeps these fundamental particles bound together with the building blocks of atomic nuclei.
Uncovering details of the entanglement between quarks and gluons could help scientists research deeper problems in nuclear physics... (MORE - missing details)
PAPER: https://iopscience.iop.org/article/10.10...633/ad910b
25-year update on the “Millennium problems” in physics
https://bigthink.com/starts-with-a-bang/...s-physics/
KEY POINTS: Back in 1900, David Hilbert presented 23 unsolved problems to challenge mathematicians over the next century; in 2000, physicists did something very similar. In the year 2000, physicists gathered to compose a list of the 10 most important unsolved problems in fundamental physics, with physics legends Michael Duff, David Gross, and Ed Witten comprising the selection panel. Now, at the start of 2025, a quarter of a century has passed, but most of these “millennium problems” remain just as obscure as ever. Here’s the progress we have, and haven’t, made.
EXCERPT: Problem #5: Why does the universe appear to have one time and three space dimensions? (submitted by Shamit Kachru, Sunil Mukhi, & Hiroshi Ooguri)
Here in our Universe, it’s verifiably measurable that there are three dimensions of space and one (and only one) dimension of time. Forces, like electromagnetism and gravity, spread out in three dimensions as you move farther away from the sources (i.e., charges) that generate those forces, which explains why they obey an inverse-square relation. However, it seems that many other options could have been possible, and that if there are further unifications to the forces, including a potential theory of everything, it would imply that our Universe once existed with several “extra dimensions” within it: a key prediction of string theory.
From a theoretical point of view, we have no idea what the dynamics would be that would take us from a full string theory — which predicts (at least) a 10-dimensional spacetime governed by a Brans-Dicke-like (scalar + tensor) theory of gravity, along with an enormous spectrum of particles and interactions — to the Universe we find ourselves in today: with only a 4-dimensional spacetime with no scalar contributions to gravity, with the restricted (Standard Model-only) spectrum of particles and interactions we observe. I once likened this process to that of an unlikely broken box, and despite a further 25 years of work on this puzzle, the best answer physicists have to offer is to mutter something qualitative about “compactification” without any known mechanism or quantitative process that can be tested.
In other words, this is another question that we are no closer to answering in 2025 than we were 25 years ago... (MORE - missing details)
LIST OF OVERALL UNSOLVED PROBLEMS IN PHYSICS: https://en.wikipedia.org/wiki/List_of_un...in_physics
https://www.space.com/spooky-action-smal...rks-gluons
EXCERPTS: . . . "Before we did this work, no one had looked at entanglement inside of a proton in experimental high-energy collision data,” team member and Brookhaven Lab physicist Zhoudunming Tu said in a statement. "For decades, we’ve had a traditional view of the proton as a collection of quarks and gluons, and we’ve been focused on understanding so-called single-particle properties, including how quarks and gluons are distributed inside the proton.
"Now, with evidence that quarks and gluons are entangled, this picture has changed. We have a much more complicated, dynamic system."
The team's research, the culmination of six years of work, refines scientists' understanding of how entanglement influences the structure of protons.
[...] Comparing HERA data with the entropy calculations, the team's results matched their predictions perfectly, providing strong evidence that quarks and gluons inside protons are maximally entangled.
"Entanglement doesn't only happen between two particles but among all the particles," Kharzeev said. "Maximal entanglement inside the proton emerges as a consequence of strong interactions that produce a large number of quark-antiquark pairs and gluons."
The revelation of maximal entanglement of quarks and gluons within protons could help reveal what keeps these fundamental particles bound together with the building blocks of atomic nuclei.
Uncovering details of the entanglement between quarks and gluons could help scientists research deeper problems in nuclear physics... (MORE - missing details)
PAPER: https://iopscience.iop.org/article/10.10...633/ad910b
25-year update on the “Millennium problems” in physics
https://bigthink.com/starts-with-a-bang/...s-physics/
KEY POINTS: Back in 1900, David Hilbert presented 23 unsolved problems to challenge mathematicians over the next century; in 2000, physicists did something very similar. In the year 2000, physicists gathered to compose a list of the 10 most important unsolved problems in fundamental physics, with physics legends Michael Duff, David Gross, and Ed Witten comprising the selection panel. Now, at the start of 2025, a quarter of a century has passed, but most of these “millennium problems” remain just as obscure as ever. Here’s the progress we have, and haven’t, made.
EXCERPT: Problem #5: Why does the universe appear to have one time and three space dimensions? (submitted by Shamit Kachru, Sunil Mukhi, & Hiroshi Ooguri)
Here in our Universe, it’s verifiably measurable that there are three dimensions of space and one (and only one) dimension of time. Forces, like electromagnetism and gravity, spread out in three dimensions as you move farther away from the sources (i.e., charges) that generate those forces, which explains why they obey an inverse-square relation. However, it seems that many other options could have been possible, and that if there are further unifications to the forces, including a potential theory of everything, it would imply that our Universe once existed with several “extra dimensions” within it: a key prediction of string theory.
From a theoretical point of view, we have no idea what the dynamics would be that would take us from a full string theory — which predicts (at least) a 10-dimensional spacetime governed by a Brans-Dicke-like (scalar + tensor) theory of gravity, along with an enormous spectrum of particles and interactions — to the Universe we find ourselves in today: with only a 4-dimensional spacetime with no scalar contributions to gravity, with the restricted (Standard Model-only) spectrum of particles and interactions we observe. I once likened this process to that of an unlikely broken box, and despite a further 25 years of work on this puzzle, the best answer physicists have to offer is to mutter something qualitative about “compactification” without any known mechanism or quantitative process that can be tested.
In other words, this is another question that we are no closer to answering in 2025 than we were 25 years ago... (MORE - missing details)
LIST OF OVERALL UNSOLVED PROBLEMS IN PHYSICS: https://en.wikipedia.org/wiki/List_of_un...in_physics