Novel beams made of twisted atoms

Scientists can now theoretically construct atomic beams of a particular kind

2013-08-07

(Press-News.org) Physicists have, for the first time, now built a theoretical construct of beams made of twisted atoms. These findings by Armen Hayrapetyan and colleagues at Ruprecht-Karls-University Heidelberg in Germany are about to be published in EPJ D. These so-called atomic Bessel beams can, in principle, have potential applications in quantum communication as well as in atomic and nuclear processes.

The concept for twisted atom beams stems from a similar approach with twisted photon beams, which are currently used as optical tweezers, for instance. It was later extended to twisted electron beams, which are used to improve the magnetic mapping of biological specimens and magnetic materials by means of twisted electron microscopy.

The authors focused on a beam made of twisted two-level atoms, which are driven by a laser field. They created a theoretical construct by using an equation, referred to as the non-relativistic Schrödinger equation, for atoms which are moving much slower than the speed of light. Hayrapetyan and colleagues solved this equation by taking into account the propagation directions of both the atomic and laser beams. By superimposing a multitude of plane waves with well-defined amplitudes, they produced Bessel beams for two-level atoms that resonantly interact with the laser field.

The authors confirmed that their atomic beams fulfilled the two main characteristics of Bessel beams. First, they showed that these beams carry a non-zero orbital angular momentum, as reflected by a rotation of the beam's wave front around the propagation axis in a corkscrew-like manner. Second, by taking a snapshot of the atomic beam intensity they demonstrated that these beams do not spread along the propagation axis. Moreover, they were able to control the profile of laser-driven atomic Bessel beams by tuning the parameters of both the atomic and laser beams.

###

Reference:

A.G. Hayrapetyan et al. (2013), Bessel beams of two-level atoms driven by a linearly polarized laser field, European Physical Journal D, DOI 10.1140/epjd/e2013-30191-x

For more information visit: http://www.epj.org

The full-text article is available to journalists on request.

ELSE PRESS RELEASES FROM THIS DATE:

Engineers gain new insight into turbulence that could lead to significant global energy savings

2013-08-07

Scientists have developed a new understanding of how turbulence works, which could help to optimise vehicle performance and save billions in global energy costs. Dr Ati Sharma, a senior lecturer in aerodynamics and flight mechanics at the University of Southampton, has been working in collaboration with Beverley McKeon, professor of aeronautics and associate director of the Graduate Aerospace Laboratories at the California Institute of Technology (Caltech) to build models of turbulent flow. Recently, they developed a new and improved way of predicting the composition ...

Quasar observed in 6 separate light reflections

2013-08-07

Quasars are active black holes -- primarily from the early universe. Using a special method where you observe light that has been bent by gravity on its way through the universe, a group of physics students from the Niels Bohr Institute have observed a quasar whose light has been deflected and reflected in six separate images. This is the first time a quasar has been observed with so many light reflections. The results are published in the scientific journal, Astrophysical Journal. INFORMATION: Article in Astrophysical Journal: http://stacks.iop.org/0004-637X/773/146 For ...

Self-healing solar cells 'channel' natural processes

2013-08-07

To understand how solar cells heal themselves, look no further than the nearest tree leaf or the back of your hand. The "branching" vascular channels that circulate life-sustaining nutrients throughout leaves and hands serve as the inspiration for solar cells that can restore themselves efficiently and inexpensively. In a new paper, North Carolina State University researchers Orlin Velev and Hyung-Jun Koo show that creating solar cell devices with channels that mimic organic vascular systems can effectively reinvigorate solar cells whose performance ...

New insights into the 1-in-a-million lightning called 'ball lightning'

2013-08-07

One of the rare scientific reports on the rarest form of lightning -- ball lightning -- describes better ways of producing this mysterious phenomenon under the modern laboratory conditions needed to explain it. The new study on a phenomenon that puzzled and perplexed the likes of Aristotle 2,300 years ago and Nikola Tesla a century ago appears in ACS' The Journal of Physical Chemistry A. C. Michael Lindsay and colleagues explain that ball lightning consists of a floating, glowing ball that may drift eerily through the sky and then explode violently, sometimes injuring ...

A greener, more sustainable source of ingredients for widely used plastics

2013-08-07

A new process can convert a wide variety of vegetable and animal fats and oils -- ranging from lard to waste cooking oil -- into a key ingredient for making plastics that currently comes from petroleum, scientists say. Their report on the first-of-its-kind process appears in the journal ACS Sustainable Chemistry & Engineering. Douglas Neckers and Maria Muro-Small explain that many of the plastics found in hundreds of everyday products begin with a group of chemical raw materials termed olefins that come from petroleum. They include ethylene, propylene and butadiene, ...

Gold 'nanoprobes' hold the key to treating killer diseases

2013-08-07

Researchers at the University of Southampton, in collaboration with colleagues at the University of Cambridge, have developed a technique to help treat fatal diseases more effectively. Dr Sumeet Mahajan and his group at the Institute for Life Sciences at Southampton are using gold nanoprobes to identify different types of cells, so that they can use the right ones in stem cell therapies. Stem cell therapy is in its infancy, but has the potential to change the way we treat cancer and other life-threatening diseases, by replacing damaged or diseased cells with healthy ones. ...

New high-tech laser method allows DNA to be inserted 'gently' into living cells

2013-08-07

WASHINGTON, Aug. 7—The applications of gene therapy and genetic engineering are broad: everything from pet fish that glow red to increased crop yields worldwide to cures for many of the diseases that plague humankind. But realizing them always starts with solving the same basic scientific question—how to "transfect" a cell by inserting foreign DNA into it. Many methods already exist for doing this, but they tend to be clumsy and destructive, not allowing researchers to precisely control how and when they insert the DNA or requiring them to burn through large numbers of ...

Loss of MicroRNA decoy might contribute to development of soft-tissue sarcoma

2013-08-07

COLUMBUS, Ohio – Researchers have discovered a novel mechanism responsible for the loss of a critical tumor-suppressor gene in rhabdomyosarcoma and other soft-tissue sarcomas, rare cancers that strike mainly children and often respond poorly to treatment. Their cause is largely unknown. Knowledge of the mechanism could guide the development of more effective therapies for these malignancies, say researchers who led the study at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Research Institute (OSUCCC – James). The ...

Is sous vide cooking safe?

2013-08-07

The Institute of Food Research (IFR) has been undertaking research for the Food Standards Agency to establish if the cooking technique sous vide is safe. Sous vide uses lower temperatures to improve food quality and could be a step closer to being more widely adopted after Institute of Food Research scientists assessed the steps needed to ensure the process is safe. Sous vide cooking involves vacuum packing food in a plastic pouch and then heating in a water bath. Chefs are attracted to the precise nature of the temperature control, allowing innovative use of the technology ...

NOAA report highlights climate change threats to nation's estuaries

2013-08-07

The nation's 28 National Estuarine Research Reserves (NERR) are experiencing the negative effects of human and climate-related stressors according to a new NOAA research report from the National Ocean Service. The national study, Climate Sensitivity of the National Estuarine Research Reserve System, points to three East Coast reserves, Sapelo Island NERR in Georgia, ACE Basin NERR in South Carolina and Waquoit Bay NERR in Massachusetts, and the Tijuana River NERR on the California-Mexico border, as the most sensitive to climate change. "The National Estuarine Research ...

Modular assembly of chiral nitrogen-bridged rings achieved by palladium-catalyzed diastereoselective and enantioselective cascade cyclization reactions

Sally C. Morton, executive vice president of ASU Knowledge Enterprise, presents a bold and practical framework for moving research from discovery to real-world impact

Novel beams made of twisted atoms

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: