Ephemeral vacuum particles induce speed-of-light fluctuations

New research shows that the speed of light may not be fixed after all, but rather fluctuates

2013-03-25

(Press-News.org) Two forthcoming EPJ D papers challenge established wisdom about the nature of vacuum. In one paper, Marcel Urban from the University of Paris-Sud, located in Orsay, France and his colleagues identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual particles with fluctuating energy values. As a result, the inherent characteristics of vacuum, like the speed of light, may not be a constant after all, but fluctuate. Meanwhile, in another study, Gerd Leuchs and Luis L. Sánchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany, suggest that physical constants, such as the speed of light and the so-called impedance of free space, are indications of the total number of elementary particles in nature.

Vacuum is one of the most intriguing concepts in physics. When observed at the quantum level, vacuum is not empty. It is filled with continuously appearing and disappearing particle pairs such as electron-positron or quark-antiquark pairs. These ephemeral particles are real particles, but their lifetimes are extremely short.

In their study, Urban and colleagues established, for the first time, a detailed quantum mechanism that would explain the magnetisation and polarisation of the vacuum, referred to as vacuum permeability and permittivity, and the finite speed of light. This finding is relevant because it suggests the existence of a limited number of ephemeral particles per unit volume in a vacuum. As a result, there is a theoretical possibility that the speed of light is not fixed, as conventional physics has assumed. But it could fluctuate at a level independent of the energy of each light quantum, or photon, and greater than fluctuations induced by quantum level gravity. The speed of light would be dependent on variations in the vacuum properties of space or time. The fluctuations of the photon propagation time are estimated to be on the order of 50 attoseconds per square meter of crossed vacuum, which might be testable with the help of new ultra-fast lasers.

Leuchs and Sanchez-Soto, on the other hand, modelled virtual charged particle pairs as electric dipoles responsible for the polarisation of the vacuum. They found that a specific property of vacuum called the impedance, which is crucial to determining the speed of light, depends only on the sum of the square of the electric charges of particles but not on their masses. If their idea is correct, the value of the speed of light combined with the value of vacuum impedance gives an indication of the total number of charged elementary particles existing in nature. Experimental results support this hypothesis.

### Reference M. Urban et al. (2013), The quantum vacuum as the origin of the speed of light, European Physical Journal D, DOI 10.1140/epjd/e2013-30578-7

Gerd Leuchs and Luis L. Sánchez-Soto (2013), A sum rule for charged elementary particles, European Physical Journal D, DOI 10.1140/epjd/e2013-30577-8

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

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

ELSE PRESS RELEASES FROM THIS DATE:

Glass-blowers at a nano scale

2013-03-25

Have you ever thrown into the fire - even if you shouldn't have - an empty packet of crisps? The outcome is striking: the plastic shrivels and bends into itself, until it turns into a small crumpled and blackened ball. This phenomenon is explained by the tendency of materials to pick up their original features in the presence of the right stimulus. Hence, this usually happens when heating materials that were originally shaped at high temperatures and cooled afterwards. EPFL researchers realized that this phenomenon occurred to ultrathin quartz tubes (capillary tubes) ...

A tiny grain helps reveal the history of a rock

2013-03-25

Rutile is used in ceramics and paints, but is particularly useful for finding out about the history of a rock. Where mineral deposits are found, rutile is often also present. The new methods therefore bring opportunities for strategies to find other mineral deposits, such as gold. Until now, rutile has been a relatively unknown mineral, despite not being rare. For example, rutile can be found on most sandy beaches around the world, including in Sweden. "It's incredible to see how little attention was paid to rutile until around five years ago," says geologist and ...

Reversing blood and freshening it up

2013-03-25

The blood of young and old people differs. In an article published recently in the scientific journal Blood, a research group at Lund University in Sweden explain how they have succeeded in rejuvenating the blood of mice by reversing, or re-programming, the stem cells that produce blood. Stem cells form the origin of all the cells in the body and can divide an unlimited number of times. When stem cells divide, one cell remains a stem cell and the other matures into the type of cell needed by the body, for example a blood cell.* "Our ageing process is a consequence of ...

Too much choice leads to riskier decisions, new study finds

2013-03-25

The more choices people have, the riskier the decisions they make, according to a new study which sheds light on how we behave when faced with large amounts of information. Researchers at the University of Warwick and the University of Lugano set up a gambling game in which they analysed how decision-making is affected when people are faced with a large number of potential gambles. They found that a bias in the way people gather information leads them to take more risks when they choose a gamble from a large set of options, a phenomenon which researchers have labelled ...

Storming the gates: UNC research probes how pancreatic cancers metastasize

2013-03-25

CHAPEL HILL, N.C. – Researchers at the University of North Carolina at Chapel Hill have discovered that a protein found in the cells surrounding pancreatic cancers play a role in the spread of the disease to other parts of the body. In a finding to be published in the March 25 issue of Oncogene, researchers in the lab of Carol Otey, PhD, found that the protein palladin enhances the ability of cancer-associated fibroblasts (CAFs) to assemble organelles known as invadopodia to break down the barriers between cells and create pathways for tumors to spread throughout the ...

Smokefree workplaces linked to smokefree homes in India

2013-03-25

Adults in India are substantially more likely to abstain from smoking at home if they are prohibited from smoking at work, a new study has found. According to data from the Global Adult Tobacco Survey India, 2009/2010, 64 per cent of adults who work in smokefree environments live in a smokefree home, compared with 42 per cent of those who work where smoking is permitted. The proportion of smokefree homes is higher in states with higher proportions of smokefree workplaces. The authors of the study, from Imperial College London and the Public Health Foundation of India ...

Cleverly designed vaccine blocks H5 avian influenza in models

2013-03-25

WASHINGTON, DC – March 25, 2013 – Until now most experimental vaccines against the highly lethal H5N1 avian influenza virus have lacked effectiveness. But a new vaccine has proven highly effective against the virus when tested in both mice and ferrets. It is also effective against the H9 subtype of avian influenza. The research is published online ahead of print in the Journal of Virology. The strength of the new vaccine is that it uses attenuated, rather than "killed" virus. (Killed viruses are broken apart with chemicals or heat, and they are used because they are ...

How common is 'The John Next Door'?

2013-03-25

Los Angeles, CA (March 25, 2012) While the media is replete with examples of "normal" men who seek out prostitutes regularly, how common are prostitute-seeking men and how much do they differ from men in the normal population? According to a new comparison study by Dr. Martin A. Monto, University of Portland, and Dr. Christine Milrod, only about 14% of men across the U.S. have ever paid for sex in their lives and only 1% of those men had done so in the previous year. In addition, the majority of these men do not possess any "peculiar" qualities that distinguish them from ...

Nanoparticles show promise as inexpensive, durable and effective scintillators

2013-03-25

A team of industrial and university researchers has shown that nanoparticles with sizes smaller than 10 nanometers – approximately the width of a cell membrane – can be successfully incorporated into scintillation devices capable of detecting and measuring a wide energy range of X-rays and gamma rays emitted by nuclear materials. The proof-of-concept study, described in the Journal of Applied Physics, suggests that "nanocrystals" – nanoparticles clustered together to mimic the densely-packed crystals traditionally used in scintillation devices – may one day yield radiation ...

Hybrid ribbons a gift for powerful batteries

2013-03-25

Hybrid ribbons of vanadium oxide (VO2) and graphene may accelerate the development of high-power lithium-ion batteries suitable for electric cars and other demanding applications. The Rice University lab of materials scientist Pulickel Ajayan determined that the well-studied material is a superior cathode for batteries that could supply both high energy density and significant power density. The research appears online this month in the American Chemical Society journal Nano Letters. The ribbons created at Rice are thousands of times thinner than a sheet of paper, ...

AI-generated voices which sound like you are perceived as more trustworthy and likeable, with implications for deep-fakes and manipulation

The cacao tree species (Theobroma cacao L.), from which we get chocolate, is likely about 7.5 million years old, with chloroplast genomes indicating that the current known diversity diversified during

Ephemeral vacuum particles induce speed-of-light fluctuations

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: