The European Laboratory for Particle Physics, CERN, announced the discovery of a particle with a mass of 126 GeV. That mass and the observed decay suggest it is the long-sought Higgs boson. This particle, conceived of more than 40 years ago, is the final building block in the Standard Model, which describes the structure of matter, and the force field related to it is believed to endow elementary particles with mass.
Weizmann Institute scientists, including Profs. Eilam Gross
, Ehud Duchovni
and Giora Mikenberg
, have been participants in this research from its outset, as well as taking on crucial leadership roles in ATLAS – one of the two experimental groups that announced the results. The Weizmann Institute has been instrumental in designing and constructing the large, sophisticated radiation detectors used in the ATLAS experiment, as well as in analyzing the data produced by the experiment.
How long does it take for an electron to pop out of its home and fly back into place? This is a quantum phenomenon known as tunneling, and it takes place in attoseconds – a few billionths of a billionth of a second. Dr. Nirit Dudovich
managed to measure that tiny time frame using ultra-fast laser pulses.
With one laser, she induced tunneling in some electrons, and then, with a second laser, gave those electrons a “kick” that sent them off course. Normally, electrons that return home emit a photon as they slide into place; but the ones that were kicked could not get back to their starting point and thus did not emit a photon. In another experiment, Dudovich used a similar technique to time differences in the exit speeds of electrons of different energy levels, recording a time of just 50 attoseconds – possibly one of the shortest intervals ever recorded.
State and Antistate
Can a particle be its own antiparticle? This idea, first proposed in 1937, is known as a “Majorana particle.” Last year, scientists found hints that such particles may exist when they produced complex “quasi-particles” that lack an electric charge, and therefore present a “state” that is its own “antistate.”
Prof. Yuval Oreg
and his group first suggested a way to produce such Majorana-like states in 2010, based on a few well-studied, relatively simple systems. They proposed using a “one-dimensional” (very thin) semiconductor nanowire in proximity to a standard superconductor and applying a weak magnetic field parallel to the nanowire.
Prof. Moty Heiblum
and his group, together with Oreg’s group, planned and built such an experimental apparatus and used it to find evidence for the proposed Majorana states. (Three additional groups world-wide found similar evidence for Majoranas, based on Oreg’s theoretical plan.) These Majorana-like states may, among other things, help advance such technology as quantum computing.
Mathematics and Computer Science
Secure Computing in the Cloud
As more and more computer services move into the “cloud” – networks of shared, remote servers – security becomes a pressing issue. One way of keeping information safe is to keep it in encrypted form employing fully homomorphic encryption (FHE) – a method that allows one to process data while it is still encrypted – and later decipher the encrypted, processed data in a secure manner.
Research in the group of Prof. Shafi Goldwasser
, including her student Dr. Zvika Brakerski, may help make this type of encryption a reality. The original version, proposed in 2009, demonstrated the concept, but was too unwieldy. Brakerski, together with Dr. Vinod Vaikuntanathan, Goldwasser’s former student at MIT, proposed a radically simpler scheme that speeds up processing time. They showed that a mathematical underpinning called ideal lattices, used to represent encrypted data and generate encryption keys in the original scheme, could be replaced by general lattices. Their result promises to pave a path to FHE applications and is the basis for a current large-scale implementation project.
Institute mathematician Prof. Vered Rom-Kedar
, working with medical and mathematical researchers, developed a mathematical model to describe what happens in a condition known as neutropenia, which is characterized by low counts of certain white blood cells known as neutrophils. Neutropenia is a common side effect of chemotherapy. In severe neutropenia, the risk of life-threatening infection is known to be high.
The model suggests, however, that some cases of neutropenia may not require aggressive treatment, while others might need to be treated proactively. The new model paints a picture of an immune system in a bistable state – one in which factors that don’t normally affect a healthy immune response can have a large impact in neutropenia. Thus a more detailed analysis, including not only blood counts but the functionality of a patient’s neutrophils and the permeability of their tissues to bacteria, could give doctors a more complete basis for prescribing treatment.