Tag: Physics

A match made in Megiddo

How the chemistry between archaeology and physics researchers led to groundbreaking discoveries about biblical history

Sometimes when you’ve stopped looking for a solution is exactly when it pops up. Israel Finkelstein, Jacob M. Alkow Professor of the Archaeology of Israel in the Bronze and Iron Ages, Sonia and Marco Nadler Institute of Archaeology, discovered a very interesting finding in 1998, at the archaeological excavation of Megiddo. He noticed a dig participant who did not quite fit the profile of a typical university undergraduate. 

“I sniffed around and learned that this particular student was actually a TAU professor flying under the radar. He turned out to be a very important ‘find,’” smiles Finkelstein. That student, incumbent of the Wolfson Chair in Experimental Physics Eli Piasetzky, Raymond and Beverly Sackler Faculty of Exact Sciences, was pursuing a degree in archaeology. Prof. Finkelstein pulled him aside to talk, and so began a research partnership that is still active two decades later.  

When were early Biblical texts written?

The archaeological issue of the day was mapping the chronology of the Iron Age in ancient Israel. Finkelstein challenged Piasetzky to improve the dating of remains from biblical times by using the radiocarbon method. The findings, published in professional and lay publications worldwide, rendered a new timeline of ancient Israel with lasting ramifications for biblical studies.

“Until then, the dating of texts was based on Biblical considerations,” explains Prof. Finkelstein, adding, “You can say that Biblical history was the path of the researchers, and archeology was used as a tool to prove the Bible stories were true.” He said. His article caused an uproar among researchers around the world, and he realized that he needed a more accurate dating tool and a talented mathematician to help him. Prof. Finkelstein presented his friend with a challenge – to accurately date the findings discovered in the excavations and to prove his claims.

Using the radiocarbon dating method on hundreds of items collected and tested, Prof. Piasetzky and Prof. Finkelstein presented a new and more accurate timeline in the history of ancient Israel, which was published in the New York Times, and had long-term implications for the study of the Biblical period since then.

 

The excavation site at Tel Megiddo, where it all began

Algorithms for reading ancient inscriptions

Prof. Piasetzky and Prof. Finkelstein continue their quest to reconstruct ancient history. As reported by The New York Times, they are conducting analyses to help better decipher ink inscriptions on potsherds, known as ostraca that were unearthed at an ancient fortress in the deep desert of Arad in southern Israel.

“The citadel of Arad stands like a time capsule: Active about 2,600 years ago, it was a relatively short-lived, godforsaken outpost, a five-day journey from Jerusalem, populated by maybe 30 soldiers,” describes Finkelstein. “Who inscribed the potsherds found there? Who read them? The ostraca teach us about government and about literacy in ancient Judah. If we determine when writing became a tool used by a wide swathe of society, we can shed light on when early Biblical texts were written.”

A shopping list from thousands of years ago

Prof. Piasetzky and Prof. Finkelstein have put together a team of archaeologists, historians, physicists, mathematicians, and computer scientists to analyze handwriting and determine just how many hands penned the Arad ostraca.

To do so, they employ physics techniques of multispectral imaging to reveal inscriptions and improve readability. Next, they compare handwriting by using algorithms specially developed by the team. What they found there was surprising: the new lines discovered were a letter requesting the issuance of wine and food from the warehouses of the Tel Arad fortress to one of the military units in the area. The recipient of the letter was the warehouse clerk, while the address was an officer from Beersheba.

Beyond the information about what people used to eat and drink during that time, the researchers revealed that even quartermasters knew how to read and write, and also learned a few new words that don’t appear in the Bible. “From the content of the letters we learn that literacy permeated even the low ranks of the military administration of the kingdom. If we extrapolate this data to other areas of Judea, and assume that this was the case in the civil administration and among the clergy, the level of literacy is considerable. This level of literacy is a reasonable background for the composition of Biblical texts,” explains Prof. Finkelstein.

Facing the future

After studying the past, Prof. Finkelstein and Prof. Piasetzky explain what can be done with these special technologies in the 2000s. “One may ask why a student of mathematics would be interested in developing tools for handwriting analysis of ancient inscriptions,” Prof. Piasetzky says. “But this type of analysis is also acutely needed today by, say, lawyers, banks, and the police. Furthermore, we’re finding solutions for the challenges of deciphering ink inscriptions found on uneven clay surfaces with faded markings and missing pieces. If our algorithms can analyze decayed inscriptions, think what they can do with modern-day handwriting on flat clean paper surfaces.”

Prof. Finkelstein adds: “With handwriting we face a problem of subjectivity. Scholars – all of us – come with preconceptions. We can convince ourselves that we see this or that particular letter. The computer does not have preconceptions. It measures length of strokes and angles, making numerical comparisons. Our next step is to integrate multispectral imaging at digs. This could dramatically improve excavation methodologies by determining on site if a potsherd is treasure or junk. One inscription can change the way we understand history.”

Featured image: Prof. Eli Piasetzky and Prof. Israel Finkelstein talk about how it all started

Conversations in the Clean Room

At the shared laboratories of the Center for Nanoscience and Nanotechnology, casual conversations between scientists can lead to breakthroughs

A chemist and a physicist walk into a clean room. No, this is not the one about how many people it takes to change a light bulb. Nor is it the one about two Israelis and three opinions. This is a true story about how two doctoral students from different fields got talking and realized that they may be able to use chemistry to solve a nagging problem in physics. “These students were the best kind – curious and open to new ideas and different ways of approaching a problem,” says Prof. Gil Markovich of the Raymond and Beverly Sackler School of Chemistry. Prof. Yoram Dagan, Raymond and Beverly Sackler School of Physics and Astronomy, nods in agreement.

Markovich and Dagan were the students’ respective PhD advisors and quickly saw the benefit of collaborating. In their research, they sought a solution to prevent damage to the surface of semiconductors – small components that control electrical current in devices such as computers and mobile phones, which damage the functioning of the devices.

For this kind of research, a particularly sterile laboratory is required. The special conditions in the “clean room” include a constant temperature of 20 degrees, 50 percent humidity, and a very powerful filter that prevents the entry of dust particles into the laboratory space and is responsible for creating a sterile work environment. These conditions are essential for the production of certain materials, especially electronic chips, which can be disrupted by something as tiny as a grain of dust.

From cell phones to thermal cameras  

The scientists are using a chemical rather than physical process to create an electrical insulating thin film the thickness of a single atom. According to Dagan, “Unlike in physics, where non-organic materials are used, we used organic compounds to get the components that create the atom-thick layer.” In the process carried out by the scientists, they heated organic compounds to the point of dissolution. Once they touch the surface, they receive additional energy and break down until the process stops on its own. “This creates only a single layer of the insulating material, because there is not enough energy to form another layer,” Dagan explains. “In a cheap and rapid chemical process, we were able to offer an alternative to complicated and costly processes, and even to achieve a better result.”

Their invention could improve microelectronics in all the devices we carry in our pockets and have in our homes by making them faster, more efficient and more compact. “This is a long-term project – an idea that may be implementable twenty years down the line. Yet exploring this basic physics problem using nano-chemistry led us to an application that can be realized today,” says Dagan.

Markovich and Dagan have teamed up with industry experts for guidance in applying their technology to improve resolution in infrared cameras used for defense and security installations. The Israel Innovation Authority (formerly the Office of the Chief Scientist) has invested in the project with a grant reserved solely for projects that have a good chance to be commercialized in Israel. “It all begins, though, with basic science. Basic science is the foundation of knowledge. When we discover new possibilities and new materials, applications can grow,” stresses Dagan.

Collaboration opens new possibilities

Markovich and Dagan share a passion for unlocking the secrets of the universe: “We are both interested in origins,” says Dagan. “Gil researches the interaction of minerals with amino acids and DNA – the original building blocks of life.  I am interested in the fundamental properties of matter and materials. I would not think up chemical approaches to physical problems by myself. Our collaboration is opening up new possibilities.” says Dagan.

“This has been a fun ride,” adds Markovich. “First, Yoram is a nice person. And I never worked on these kinds of problems before. We have ideas for cooperation on chemical ways to create new materials for quantum computing. The future is wide open.” 

Featured iage:Prof. Gil Markovich and Prof. Yoram Dagan (Photo: Yoram Reshef)

Tel Aviv University Researcher Heads a Committee in Charge of the Future of the European Science

CERN Council unanimously decided to update its scientific strategy – according to the recommendation of a committee headed by Prof. Halina Abramowicz

After two years of prolonged discussions of physicists from across Europe and outside the continent, the European Organization for Nuclear Research (CERN) decided lately to update its strategy, according to the recommendation of the European Strategy for Particle Physics Update Committee (EPPSU) – headed by Prof. Halina Abramowicz from Tel Aviv University.

Prof. Halina Abramowicz: “As the head of the committee I had to coordinate the effort in its whole. At the beginning of our work at the committee, we clarified the needs of the particle physicist’s scientific community in each country, and afterwards we conducted an international analysis of the proposals’ quality.  After two years of discussions, the European scientific community reached an agreement. Fortunately, CERN Council decided to endorse the committee’s recommendations. Those are heavy financial and political decisions that are made once in a decade, and it’s not every day that Israel finds itself heading a policy-outlining committee.”

The committee headed by Prof. Abramowicz set, in effect, the CERN strategy for the fourth decade of the 21st century, after the Large Hadron Collider (LHC) research program, world’s largest particle collider, would end. The committee decided that the European particle physics’ main goal would be an electron-positron collider which will be a “power house” for the Higgs Boson particle that was discovered for the first time at the LHC. It would be followed by a new, 62-mile-long, proton-proton collider that was proposed and which is expected to surpass the energy production records of the LHC. Its cost is estimated at 25 billion dollars.

The Higgs Boson particle was discovered at the LHC in 2012 and caused a revolution in particle physics. Not only is the Higgs Boson the last missing part in the standard particle model, but it also was proven to be completely different from any other particle previously measured. The research regarding the Higgs Boson is just taking its first steps, but the particle properties, such as its light weight, already raise profound questions that the standard model cannot explain. It is very hard to accurately measure the particle, also known as the god particle, and hopefully, the new approach, recommended by Prof. Abramowicz’s committee, will allow more accurate measurements of the Higgs Boson, thus paving the way for new insights about the basic fabric of the universe.

“We are trying to understand how the universe started and what it’s made of – this is basic science,” explains Prof. Abramowicz. “But, in order to understand this we need technological advances and developments, some of which are being implemented afterwards in other fields as well. For example, the PET CT, a medical tomography test used worldwide at medical centers, was developed due to projects similar to the LHC, as well as several significant developments in Big Data processing in the Cloud Computing field. In order to examine the feasibility of the new collider, CERN works these days on developing world first magnets which will use high temperature super conductors – a development which can cause a revolution in transportation, with floating magnet trains, and those are just a few examples. We don’t know which doors would be opened to us with this new challenge that the committee made CERN face – both in basic science and in collaboration with the industry, which will be needed to build the collider.”

To achieve the ambitious ESPPU goals, particle physicists are being called to execute vigorous research and development programs (R&D) of advanced collider technologies, particularly regarding high level and high temperature super conductors. In addition, the roadmap includes R&D of plasma wakefield acceleration, as well as an international research with the option of realising a muon collider and R&D of advanced detectors.

“Israel joined CERN as a full member in 2014, and is the first and only non-European country to join,” says Prof. Abramowicz, who takes part in the “ATLAS” experiment at the LHC. “It’s our national lab. Researchers from Tel Aviv University, the Ben-Gurion University, the Hebrew University, Technion – Israel Institute of Technology, and Weizmann Institute are senior partners running experiments at the LHC. Therefore, recommendations made by the EPPSU committee are important not only to science but also to our scientific community, technology, economy and our society. ”

Featured image: Prof. Halina Abramowicz

A new, revolutionary way to simplify complex scientific calculations

Your zip software could calculate entropy as well as a supercomputer, TAU researchers say

Researchers at Prof. Roy Beck’s lab have figured out a simple and accessible solution to a problem that even supercomputers struggle with: measuring entropy, the level of molecular disorder or randomness in a complext system. In complex physical systems, the interaction of internal elements is unavoidable, rendering entropy calculation a computationally demanding, and often impractical, task. The tendency of a properly folded protein to unravel, for example, can be predicted using entropy calculations. Now, a new Tel Aviv University study proposes a radically simple and efficient way of calculating entropy — and it probably exists on your own computer. “We discovered a way to calculate entropy using a standard compression algorithm like the zip software we all have on our computers,” explains Prof. Roy Beck of TAU’s School of Physics and Astronomy. “Supercomputers are used today to simulate the folding or misfolding of proteins in diseased states. Our study demonstrated that by using a standard compression algorithm, we can provide new insights into the physical properties of these proteins by calculating their entropy values using a compression algorithm.

A veriety of new solutions

“Having the ability to calculate entropy meets an urgent need to harness the incredible power of computer simulations to address urgent, timely problems in science and medicine,” Prof. Beck adds. The research was led by him and conducted by TAU PhD students Ram Avinery and Micha Kornreich. According to Prof. Beck, the research has endless applications. From biomedical simulations to basic research conducted in physics, chemistry or material science, the new algorithm would be simple to use on any computer. “A high school student used our concept to calculate the entropy of a complex physical system — the XY model,” says Prof. Beck. “Although this is considered a challenging problem with regard to entropy, the student accomplished it with very little guidance. This demonstrates how easily this method can be used by almost anybody to solve very interesting problems.”

A by-the-way discovery

The idea for the computational method first came about when Prof. Beck’s students, Avinery and Kornreich, discussed entropy from the point of view of information theory. They wondered how well this idea might work in practice rather than in theory. “They simulated a few standard physical systems with entropy values they can compare to,” says Prof. Beck. “Soon they found that the simulation data file size after compression rises and falls just as the expected entropy should. Shortly after that, they realized they could convert the compressed file size into a usable value — the physical entropy. Surprisingly, the simple conversion they used was valid for all the systems studied.” The researchers are currently expanding the application of their methodology to a wide and varied selection of systems. “Since we started working and talking about our work, we have been approached by many researchers from very different fields, asking us to help them calculate entropy from their data,” concludes Prof. Beck. “For now, we are concentrating on simulation of protein folding, a timely and urgent topic that can benefit tremendously from our discovery.”

For the first time: The “God Particle” has been characterized in its decay into a pair of charm quarks

TAU researchers contribute further understanding of elusive elementary particle that gives mass to everything in the universe

Physicists worldwide have been captivated by the Higgs boson particle, also known as the “God Particle”. Its discovery a decade ago made waves in the physics community, and had researchers curious to learn more about its properties. TAU researchers have now succeeded, as part of a groundbreaking study, to describe a rare physical process through which the Higgs boson decays into a pair of rare elementary particles. The rate of this decay process can now be characterized more precisely and completely than before.

The new study was conducted as part of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) by Prof. Erez Etzion and doctoral students Guy Koren, Hadar Cohen and David Reikher from the Raymond and Beverly Sackler School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, at Tel Aviv University. It was a collaboration with the research team of Prof. Eilam Gross from the Weizmann Institute of Science and others.

Learning More About Forces in Nature

Over fifty years ago, physicists Prof. Peter Higgs and Prof. Francois Englert (who since 1984 has been a Sackler Fellow by special appointment in the TAU School of Physics and Astronomy) estimated that a new particle might exist whose field “provides the mass” to the elementary particles in our world.

In 2012, the end of a 30-year hunt for the Higgs boson was celebrated. Israeli researchers were senior partners in this discovery, and Prof. Halina Abramowicz, who was part of the TAU team, said “The discovery of the Higgs-like particle affirms the world view that the universe is made up of straightforward, symmetrical laws and that humans are the byproduct of disruptions in that symmetry.” Higgs and Englert won the Nobel Prize the following year.

The Challenge of Creating the Higgs boson 

In the particle accelerator, pairs of protons are made to collide with each other at extremely high velocities. In such energetic collisions, various interesting processes can occur, from which, one can learn about the nature of our universe. The way in which these processes are investigated, is by means of a complex array of particle detectors placed around the points of collision, enabling reconstruction of the types of particles that are generated during the collision, as well as their features. A vast range of processes can occur during the collisions, and each has its own unique “signature” in the detector. In order to extract rare events and acquire new insights about the elementary particles and forces in nature, large amounts of statistical data must be collected (i.e. a very large number of collisions must be observed).

The Higgs boson is, as mentioned, a relatively heavy elementary particle, but can be created in collision between protons, as long as the accelerator’s energy is high enough. Immediately after its creation, it decays into lighter particles.

“It is interesting to investigate into which types of particles the Higgs decays, and with what frequency it decays into each type of particle,” says Guy Koren. “To help answer that question, our group is trying to measure the rate at which the Higgs boson decays into particles called ‘charm quarks’.” Quarks are a specific type of particles that share similar features. They compound, for instance, the protons and neutrons, which are in the nuclei of atoms. Koren continues to explain that measuring the decay of Higgs boson into ‘charm quarks’ is not a simple mission, for two reasons: 1. Only one out of billions of collisions [between protons] result in the creation of Higgs bosons. Furthermore, only three percent of the Higgs bosons that do emerge proceed to decay into charm quarks. 2. Five additional types of quarks exist, and they all leave similar signatures in the detectors. So, even when the process does take place, it is very hard to identify.

More Information About The Rate of Decay 

Despite all the collisions that have been collected since 2012, the group from Tel Aviv has not yet identified enough decays of Higgs bosons into charm quarks to measure the rate of the process with the required statistical accuracy.

Nevertheless, sufficient data has been accumulated to state what the maximal rate of the process is with respect to the theoretical predictions. A rate of decay higher than the predicted rate would constitute a first important indicator for “new” physics or expansion of the currently accepted model – the standard model of elementary particles. From the current measurement, the researchers conclude (with a well-defined statistical certainty) that there is no chance that the rate of decay of the Higgs boson into charm quark is 8.5 (or more) times higher than the theoretical predictions, otherwise enough such decays would have been observed in order to measure it. “This is the first time that anyone has ever succeeded in saying something important about the rate of this specific decay based on a direct measurement of it, therefore it is a very important and significant statement in our field,” explains Koren

The research is not yet over, however. Higgs’ decays into quarks of smaller masses have yet to be observed. As a result, the researchers cannot be certain that the same ‘rules’ apply to quarks from those generations. “If it should appear that the Higgs boson decays at a rate that is not proportional to mass (squared) of the particles, there could be far-reaching implications for our understanding of the universe,” explains Prof. Etzion.

Featured image: Illustration: The European Organization for Nuclear Research (CERN)’s LHC accelerator, by which the Higgs boson was detected in 2012 in the ATLAS and CMS experiments

Victoria

Tok Corporate Centre, Level 1,
459 Toorak Road, Toorak VIC 3142
Phone: +61 3 9296 2065
Email: office@aftau.asn.au

New South Wales

P.O. Box 4044, Maroubra South,
NSW 2035
Phone: +61 418 465 556
Email: davidsolomon@aftau.org.au

Western Australia

P O Box 36, Claremont,
WA  6010
Phone: :+61 411 223 550
Email: clivedonner@thelinqgroup.com