Higgs excitations

Collective motions near absolute 0

2012-07-27

(Press-News.org) Phase transitions between different states of matter can be associated with a specific type of excitation called the "Higgs excitation". This phenomenon has now been ob-served in a two-dimensional quantum gas at temperatures near absolute zero.

In physics spontaneous symmetry breaking is a fundamental feature of transitions between different states of matter. An example of this phenomenon is the abrupt alignment of spin orientation in a ferromagnetic substance when the material is cooled below the so-called Curie temperature. Phase transitions introduce a new degree of order into the system, which may in turn provoke a specific type of excitation that causes the ensemble of particles to behave in a coordinated fashion. If their collective motion conforms to rules akin to those of the theory of relativity, a so-called Higgs excitation may arise.

Tracking transient excitations

The Higgs excitation plays a key role in the Standard Model of Particle Physics, where it is associated with the famous Higgs boson. But Higgs excitations can also develop in solid-state-like systems. The problem is that, as in particle physics, they are difficult to detect ex-perimentally because they rapidly decay. Higgs excitations are expected to have particularly short lifetimes in low-dimensional atomic systems. Indeed, some physicists have doubted whether they could be observed in such systems at all.

An unpredictable phenomenon

A team of researchers led by Professor Immanuel Bloch, LMU physicist and a Director at the Max-Planck-Institute of Quantum Optics, in close collaboration with theorists at several American institutions, has now experimentally detected Higgs excitations in low-dimensional systems for the first time. For the experiments, they used an ultracold two-dimensional gas made up of rubidium atoms. This system is in the vicinity of a phase transition, in a state that behaves in accordance with relativistic field theories.

"We are excited to study phenomena close to absolute zero temperature that usually occur at the highest energies", says Bloch. Furthermore, the observations allow the researchers to characterize a phenomenon that is, as yet, not fully understood theoretically. This makes the new data still more valuable. (Nature, 2012) MPQ/göd

### Publication: Manuel Endres, Takeshi Fukuhara, David Pekker, Marc Cheneau, Peter Schauß, Christian Groß, Eugene Demler, Stefan Kuhr, and Immanuel Bloch The 'Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Tran-sition Nature, 26. July, 2012

Contact: Prof. Dr. Immanuel Bloch
Chair of Quantum Physics, LMU München
Schellingstr. 4
80799 Munich and Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching
Phone: +49 (0) 89 / 32 905 -138
Email: immanuel.bloch@mpq.mpg.de

Manuel Endres
Max-Planck-Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching
Phone: +49 (0) 89 / 32 905 -214
Email: manuel.endres@mpq.mpg.de

ELSE PRESS RELEASES FROM THIS DATE:

Turbulences at a standstill

2012-07-27

For theoretical physicist Dima Shepelyansky from the CNRS-University of Toulouse, France, devising models of chaos and turbulence is his bread and butter. In a recent study published in EPJ B¹, he presents an exception he found in a model of turbulence, indicating that there are energy flows from large to small scale in confined space. Indeed, under a specific energy threshold, there are no energy flows, similar to the way electron currents and energy spreading are stopped in disordered solids. The author relies on numerical simulations to study a kind of turbulence—known ...

'Diving board' sensors key to DNA detection

2012-07-27

PHILADELPHIA - A tiny vibrating cantilever sensor could soon help doctors and field clinicians quickly detect harmful toxins, bacteria and even indicators of certain types of cancer from small samples of blood or urine. Researchers from Drexel University are in the process of refining a sensor technology that they developed to measure samples at the cellular level into an accurate method for quickly detecting traces of DNA in liquid samples. According to lead researcher Dr. Raj Mutharasan, a professor in Drexel's College of Engineering, the group's unique application ...

The longer you're awake, the slower you get

2012-07-27

Boston, MA – Anyone that has ever had trouble sleeping can attest to the difficulties at work the following day. Experts recommend eight hours of sleep per night for ideal health and productivity, but what if five to six hours of sleep is your norm? Is your work still negatively affected? A team of researchers at Brigham and Women's Hospital (BWH) have discovered that regardless of how tired you perceive yourself to be, that lack of sleep can influence the way you perform certain tasks. This finding is published in the July 26, 2012 online edition of The Journal of ...

The seat of meta-consciousness in the brain

2012-07-27

This press release is available in German. Which areas of the brain help us to perceive our world in a self-reflective manner is difficult to measure. During wakefulness, we are always conscious of ourselves. In sleep, however, we are not. But there are people, known as lucid dreamers, who can become aware of dreaming during sleep. Studies employing magnetic resonance tomography (MRT) have now been able to demonstrate that a specific cortical network consisting of the right dorsolateral prefrontal cortex, the frontopolar regions and the precuneus is activated when this ...

Boys' impulsiveness may result in better math ability, say MU researchers

$Boys impulsiveness may result in better math ability, say MU researchers$

2012-07-27

COLUMBIA, Mo. – In a University of Missouri study, girls and boys started grade school with different approaches to solving arithmetic problems, with girls favoring a slow and accurate approach and boys a faster but more error prone approach. Girls' approach gave them an early advantage, but by the end of sixth grade boys had surpassed the girls. The MU study found that boys showed more preference for solving arithmetic problems by reciting an answer from memory, whereas girls were more likely to compute the answer by counting. Understanding these results may help teachers ...

The manager as matchmaker: Finding the best fit between employee and customer

2012-07-27

CHESTNUT HILL, MA (July 27, 2012) – Matchmaking managers can improve customer relations and increase repeat business by pairing employees and customers with similar personalities, according to a report in the latest edition of the Journal of Service Research. The study by three German researchers suggests that managers use role-playing exercises, videotaped rehearsals and on-site evaluations to better determine the service experience from the customer's perspective. Then match the right employees with the right customers, report marketing professors Jan Wieseke, of Ruhr-University ...

Georgia forests, 2011

2012-07-27

Georgia contains the largest area of forest cover of any state in the South, with forests making up 67 percent of land cover or 24.8 million acres, according to a Forest Inventory Analysis (FIA) Factsheet just released by the USDA Forest Service Southern Research Station (SRS). While this land area remains stable, timber inventory has increased. "Forest area in Georgia remained relatively stable over the last 50 years," says Richard Harper, SRS forester and author of the analysis. "While forest area stayed about the same, timber inventory more than doubled over the same ...

BUSM researchers find link between childhood abuse and age at menarche

2012-07-27

(Boston) – Researchers from Boston University School of Medicine (BUSM) have found an association between childhood physical and sexual abuse and age at menarche. The findings are published online in the Journal of Adolescent Health. Researchers led by corresponding author, Renée Boynton-Jarrett, MD, assistant professor of pediatrics at BUSM, found a 49 percent increase in risk for early onset menarche (menstrual periods prior to age 11 years) among women who reported childhood sexual abuse compared to those who were not abused. In addition, there was a 50 percent increase ...

Swaziland HIV incidence results announced at AIDS 2012

2012-07-27

The results from a nationally representative HIV incidence study in Swaziland indicate that the national rate of new HIV infections is 2.38% among adults ages 18-49. This figure, comparable to the 2009 UNAIDS estimate of 2.66% for Swaziland adults ages 15-49, suggests that the HIV epidemic in Swaziland may have begun to stabilize in the past few years. The findings of the Swaziland HIV Incidence Measurement Survey (SHIMS) were presented today at the XIX International AIDS Conference in Washington DC. "The country continues to have very high HIV incidence rates. Since ...

Estimate: A new Amish community is founded every 3 and a half weeks in US

2012-07-27

COLUMBUS, Ohio – A new census of the Amish population in the United States estimates that a new Amish community is founded, on average, about every 3 ½ weeks, and shows that more than 60 percent of all existing Amish settlements have been founded since 1990. This pattern suggests the Amish are growing more rapidly than most other religions in the United States, researchers say. Unlike other religious groups, however, the growth is not driven by converts joining the faith, but instead can be attributed to large families and high rates of baptism. In all, the census counts ...

Higgs excitations

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: