Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Physicists Use Black Hole Studies to Measure Photon Mass

A global team of scientists, including a University of Mississippi physicist, has determined the best constraint on the mass of photons so far, using observations of super-massive black holes.

The research findings appear in the September issue of Physical Review Letters. "Black hole bombs and photon mass bounds" is co-authored by Emanuele Berti, UM assistant professor of physics and astronomy, along with fellow researchers Paolo Pani, Vitor Cardoso, Leonardo Gualtieri and Akihiro Ishibashi.

Illustration by Ana Sousa.

Schematic illustration of the 'black hole bomb' effect. A wave thrown at a black hole can be magnified upon reflection, extracting rotational energy and spinning down the black hole. The mass of the particle acts like a 'wall' for outgoing waves (represented by the enclosing sphere in this figure), so the reflection/amplification process is repeated and causes an instability.

The paper details how the scientists, who work in Portugal, Italy, Japan and the U.S., found a way to use astrophysical observations to test a fundamental aspect of the Standard Model – namely, that photons have no mass – better than anyone before.

"The test works like this: if photons had a mass, they would trigger an instability that would spin down all black holes in the universe," Berti said. "But astronomers tell us that the gigantic, super-massive black holes at galactic centers are spinning, so this instability cannot be too strong.

"The mass of the photon, if it has a mass at all, must be extremely tiny."

"Ultralight photons with nonzero mass would produce a 'black hole bomb': a strong instability that would extract energy from the black hole very quickly," said Pani, the paper's lead author. "The very existence of such particles is constrained by the observation of spinning black holes. With this technique, we have succeeded in constraining the mass of the photon to unprecedented levels: the mass must be one hundred billion of billions times smaller than the present constraint on the neutrino mass, which is about two electron-volts."

The results of this study can be used to investigate the existence of new particles, such as those possibly contributing to the dark matter that is the subject of a search using the Large Hadron Collider at CERN in Geneva. CERN is the site where the breakthrough discovery of the Higgs boson was reported earlier this year.

"That discovery filled one of the most important gaps in our understanding of the standard model of particle physics, because it explains how particles get their mass," Gualtieri said. "However, not all particles have mass. Physics makes progress by testing every nook and cranny of our commonly accepted theories. So, if we believe that a particle has no mass, we'd better test this idea with precise experiments.

"Observations of super-massive black holes may provide new insights which are not accessible in laboratory experiments. This would certainly be exciting. Perhaps these new frontiers in astrophysics will give us a clearer understanding of the microscopic universe."

"Paolo, Vitor, Leonardo and I are all part of an IRSES Network on 'Numerical Relativity and High-Energy Physics' funded by the European Union," Berti said. "Paolo presented a talk on this work at the first meeting of our network that was held in Aveiro, Portugal in July. This network will be used in the next four years to strengthen our collaboration even further."

Pani, who received the Fubini Prize from the Italian National Institute of Nuclear Physics for the best Ph.D. thesis nationwide in 2011, is a post-doctoral researcher at Instituto Superior Técnico in Lisbon, Portugal, supported by a European Marie Curie Fellowship.

"Paolo started working with us when he visited Ole Miss in 2007," Berti said. "We have been working together on this particular project since January 2012, and we have co-authored nine papers so far."

A post-doctorate researcher at UM before returning to his native Portugal, Cardoso is a professor at Instituto Superior Tecnico, where his group is supported by a prestigious European Research Council Starting Grant. Cardoso and Berti have published 37 papers together over the past decade.

"Gualtieri and I were both Ph.D. students under the supervision of Valeria Ferrari in Rome, Italy," Berti said. "We have also been collaborating for more than a decade. Leonardo is now a research professor ('ricercatore') in Rome."

Ishibashi works at the KEK Theory Center and at the Department of Physics of Kinki University in Japan, where physicists at the center are studying in great depth phenomena similar to the one described in the PRL paper.

This study was funded, in part, by National Science Foundation Grant No. PHY-0900735 and by CAREER Grant No. PHY-1055103.

To view the team's PRL paper before publication, go to or A “New Scientist” article featuring their work can be read at

For more information about the UM Department of Physics and Astronomy, go to

(edwin smith)

For more news from the University of Mississippi, visit

Edwin Smith | Newswise Science News
Further information:

More articles from Physics and Astronomy:

nachricht Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>