Heavy ion collisions at CERN should be able to produce the shortest light pulses ever created. This was demonstrated by computer simulations at the Vienna University of Technology.
The pulses are so short that they cannot even be measured by today's technological equipment. Now, a method has been proposed to create the world's most precise stopwatch for the world's shortest light pulses, using a detector which is going to be installed at CERN in 2018.
Small, Short and Hot
Phenomena taking place on very short time scales are often investigated using ultra short laser pulses. Today, pulse durations of the order of attoseconds (billionths of a billionths of a second, 10^-18 seconds) can be created. But these records could soon be broken: "Atomic nuclei in particle colliders like the LHC at CERN or at RHIC can create light pulses which are still a million times shorter than that", says Andreas Ipp from TU Vienna.
In the ALICE experiment at CERN, lead nuclei are collided almost at the speed of light. The debris of the scattered nuclei together with new particles created by the power of the impact form a quark-gluon plasma, a state of matter which is so hot that even protons and neutrons melt. Their building blocks – quarks and gluons – can move independently without being bound to each other. This quark-gluon plasma only exists for several yoctoseconds (10^-24 seconds).
Ideas From Astronomy
From the quark-gluon plasma created in a particle collider, light pulses can be emitted, which carry valuable information about the plasma. However, conventional measurement techniques are much too slow to resolve flashes on a yoctosecond timescale. "That's why we make use of the Hanbury Brown-Twiss effect, an idea which was originally developed for astronomical measurements", says Andreas Ipp.
In a Hanbury Brown-Twiss experiment, correlations between two different light detectors are studied. That way, the diameter of a star can be calculated very precisely. "Instead of studying spatial distances, the effect can just as well be used for measuring time intervals", says Andreas Ipp. The calculations he did together with Peter Somkuti show that the yoctosecond pulses of the quark-gluon plasma could be resolved by a Hanbury Brown-Twiss experiment. "It would be hard to do, but it would definitely be achievable", says Ipp. This experiment would not require any additional expensive detectors, it could be done with the "forward calorimeter", which is supposed to go on line at CERN in 2018. That way, the ALICE-experiment could become the world's most accurate stopwatch.
The Enigmas of the Plasma
There are still many open questions in quark-gluon plasma physics. It has an extraordinarily low viscosity, it is thinner than any liquid we know. Even if it starts out in a state of extreme disequilibrium, it reaches a thermal equilibrium extremely fast. Studying the light pulses from the quark-gluon plasma could yield valuable new information to better understand this state of matter.
In the future, the light pulses could perhaps even be used for nuclear research. "Experiments using two light pulses are often used in quantum physics", says Andreas Ipp. "The first pulse changes the state of the object under investigation, a second pulse is used shortly after that, to measure the change." With yoctosecond light pulses, this well-established approach could be used in areas which up until now have been completely inaccessible to this kind of research.
Dr. Andreas Ipp
Institute for Theoretical Physics
Vienna University of Technology
Wiedner Hauptstr. 8-10, 1040 Vienna
T: +43 1 58801 13635
Florian Aigner | Source: EurekAlert!
Further information: www.tuwien.ac.at
Further Reports about: astronomical measurements > atomic nuclei > building block > CERN > computer simulation > Hanbury Brown-Twiss experiment > information technology > Light pulses > quark-gluon plasma > yoctosecond timescale
More articles from Physics and Astronomy:
Detecting mirror molecules
23.05.2013 | Harvard University
Researchers Explain Magnetic Field Misbehavior in Solar Flares: The Culprit is Turbulence
23.05.2013 | Johns Hopkins University
New indicator molecules visualise the activation of auto-aggressive T cells in the body as never before
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to examine individual cells and their activity directly in the tissue.
The development of new microscopes and fluorescent dyes in ...
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
University of Würzburg physicists have succeeded in creating a new type of laser.
Its operation principle is completely different from conventional devices, which opens up the possibility of a significantly reduced energy input requirement. The researchers report their work in the current issue of Nature.
It also emits light the waves of which are in phase with one another: the polariton laser, developed ...
Innsbruck physicists led by Rainer Blatt and Peter Zoller experimentally gained a deep insight into the nature of quantum mechanical phase transitions.
They are the first scientists that simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders. They have published the results of their work in the journal Nature Physics.
“When water boils, its molecules are released as vapor. We call this ...
23.05.2013 | Physics and Astronomy
23.05.2013 | Health and Medicine
23.05.2013 | Ecology, The Environment and Conservation
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News