. | . |
Russian and German physicists developed a mathematical model of trapped atoms and ions by Staff Writers Moscow, Russia (SPX) Sep 19, 2018
It is difficult to study processes at the level of individual atoms and ions at room temperature due to their thermal motion. It causes disturbance that is the reason for considerable inaccuracy of measurements. The main cause of observation errors is the Doppler effect. However, if the atoms are cooled down and therefore the speed of their thermal motion is reduced, this effect can be suppressed. Atoms can be cooled down using a laser, but it's important to select proper frequency and direction. The same laser can create a so-called trap for cooled down atoms - a standing light wave (i.e. a wave that does not move but fluctuates in one place) keeps the atoms fixed in confined region of space. This trap can be compared to an egg case that prevents the eggs from moving around. Such a trap can be used as a model system for studying various quantum processes - from solid state physics to high energy physics. However, it is quite difficult to give a detailed mathematical description of the systems that consist of trapped quantum particles. "The two-body problem (e.g. a hydrogen atom or two colliding atoms) is the basis of quantum mechanics. Each body has three coordinates (X, Y, and Z, just like your Maths teacher told you). In free space this problem may be reduced to relative motion of two particles by separation of their center-of-mass. The number of variables left in the problem is now three instead of six. The absence of a preferred direction helps reduce this problem to an even simpler one-dimensional radial equation (i.e. an equation with one variable) by separation of angular variables. But when two quantum particles are trapped, an additional condition appears, which is preferential direction. In this case the problem cannot be reduced to a one-dimensional equation. It becomes two-dimensional if the atoms are identical and six-dimensional if they are distinguishable or if an atom-ionic system is considered. Many scientists are able to solve two-dimensional equations, but three-dimensional ones are already quite a complicated problem for modern numerical mathematics. This is the area where new methods have to be developed," said Vladimir Melezhik, the author of the study, the doctor of science in physics and mathematics from RUDN. Together with physicists from the University of Hamburg Vladimir Melezhik developed a mathematical method reducing multi-dimensional calculations to a system of one-dimensional equations to simplify and speed up the calculations. The authors used it to describe atomic systems with different parameters (intensity of effective interparticle interaction, initial state population, and particle energy). The method proved to be also applicable to hybrid atom-ionic systems. If not only atoms, but also ions are trapped, new complex quantum effects can be studied. The developed algorithm provides for the calculation of collisions of atoms and ions to each other and the laser trap. In the future such hybrid structures potentially can help to model the elements of quantum computers.
Just seven photons can act like billions London, UK (SPX) Sep 11, 2018 A system made of just a handful of particles acts just like larger systems, allowing scientists to study quantum behaviour more easily. Most substances physicists study are made up of huge numbers of particles - so large that there is essentially no difference between the behavioural properties of a drop or a swimming pool's worth of pure water. Even a single drop can contain more than a quadrillion particles. This makes understanding their collective behaviour relatively easy. For example, ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |