Quarks are found in each proton and are bound together by forces which cause all other known forces of nature to fade. To understand the effects of these strong forces between the quarks is one of the greatest challenges in modern particle physics.
New theoretical results from the Niels Bohr Institute show that enormous quantities of random numbers can describe the way in which quarks 'swing' inside the protons. The results have been published in arXiv and will be published in the journal Physical Review Letters.
Just as we must subject ourselves, for example, to the laws of gravity and not just float around weightless, quarks in protons are also subject to the laws of physics. Quarks are one of the universe's smallest, known building blocks. Each proton inside the atomic nucleus is made up of three quarks and the forces between the quarks are so strong that they can never – under normal circumstances, escape the protons
Left- and right-handed quarks
The quarks combined charges give the proton its charge. But if you add up the masses of the quarks you do not get the mass of the proton. Instead, the mass of the proton is dependent on how the quarks swing. The oscillations of the quarks are also central for a variety of physical phenomena. That is why researchers have worked for years to find a theoretical method for describing the oscillations of quarks.
The two lightest quarks, 'up' and 'down' quarks, are so light that they can be regarded as massless in practice. There are two types of such massless quarks, which might be called left-handed and right-handed. The mathematical equation governing quarks' movements show that the left-handed quarks swing independently of the right-handed. But in spite of the equation being correct, the left-handed quarks love to 'swing' with the right-handed.
Spontaneous symmetry breaking
"Even though this sounds like a contradiction, it is actually a cornerstone of theoretical physics. The phenomenon is called spontaneous symmetry breaking and it is quite easy to illustrate", explains Kim Splittorff, Associate Professor and theoretical particle physicist at the Niels Bohr Institute, and gives an example: A dance floor is filled with people dancing to rhythmic music. The male dancers represent the left-handed quarks and the female dancers the right-handed quarks. All dance without dance partners and therefore all can dance around freely. Now the DJ puts on a slow dance and the dancers pair off. Suddenly, they cannot spin around freely by themselves. The male (left-handed) and female (right-handed) dancers can only spin around in pairs by agreeing on it. We say that the symmetry 'each person swings around, independent of all others' is broken into a different symmetry 'a pair can swing around, independent of other pairs'.
Similarly for quarks, it is the simple solution that the left-handed do not swing with the right-handed. But a more stabile solution is that they hold onto each other. This is spontaneous symmetry breaking.
Dance to random tones
"Over several years it became increasingly clear that the way in which the left-handed and right-handed quarks come together can be described using a massive quantities of random numbers. These random numbers are elements in a matrix, which one may think of as a Soduko filled in at random. In technical jargon these are called Random Matrices", explains Kim Splittorff, who has developed the new theory together with Poul Henrik Damgaard, Niels Bohr International Academy and Discovery Center and Jac Verbaarschot, Stony Brook, New York.
Even though random numbers are involved, what comes out is not entirely random. You could say that the equation that determines the oscillations of the quarks give rise to a dance determined by random notes. This description of quarks has proven to be extremely useful for researchers who are looking for a precise numerical description of the quarks inside a proton.
It requires some of the most advanced supercomputers in the world to make calculations about the quarks in a proton. The central question that the supercomputers are chewing on is how closely the left-handed and right-handed quarks 'dance' together. These calculations can also show why the quarks remain inside the protons.
One problem up until now has been that these numerical descriptions have to use an approximation to the 'real' equation for the quarks. Now the three researchers have shown how to correct for this so that the quarks in the numerical calculations also 'swing' correctly to random numbers.
New understanding of the data
"Using our results we can now describe the numerical calculations from large research groups at CERN and leading universities very accurately", says Kim Splittorff.
"What is new about our work is that not only the exact equation for quarks, but also the approximation, which researchers who work numerically have to use, can be described using random matrices. It is already extremely surprising that the exact equation shows that the quarks swing by random numbers. It is even more exciting that the approximation used for the equation has a completely analogous description. Having an accurate analytical description available for the numerical simulations is a powerful tool that provides an entirely new understanding of the numerical data. In particular, we can now measure very precisely how closely the right-handed and left-handed quarks are dancing", he says about the new perspectives in the world of particle physics.
Article in arXiv: http://arxiv.org/pdf/1001.2937v3
Kontact:Kim Splittorff, Associate Professor, PhD in theoretical high energy physics.
Gertie Skaarup | EurekAlert!
Gamma ray camera offers new view on ultra-high energy electrons in plasma
28.10.2016 | American Physical Society
Scientists measure how ions bombard fusion device walls
28.10.2016 | American Physical Society
Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.
So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
28.10.2016 | Power and Electrical Engineering
28.10.2016 | Physics and Astronomy
28.10.2016 | Life Sciences