When most people think of quantum mechanics they think of Schroedinger's cat, a thought experiment describing a cat inside a closed box, that may be either dead or alive. Only when the classical physics world enters the box do we know. But what is the tipping-point between that cat's life and death, when does quantum behavior give way to classical physics?
Where, on the small scale, is Schroedinger's cat small enough size to be perceived as being both alive and dead at the same time?
A new study in Physical Review Letters has an answer, thanks to a fiber-based nonlinear process that allowed physicists to observe how, and under what conditions, classical physical behavior emerges from the quantum world.
Spring is finally in, and with it the great expectations for a new run of the Large Hadron Collider, which will restart in a month or so with a 62.5% increase in center of mass energy of the proton-proton collisions it produces: 13 TeV. At 13 TeV, the production of a 2-TeV Z' boson, say, would not be so terribly rare, making a signal soon visible in the data that ATLAS and CMS are eager to collect.
It is often claimed that the Ancient Greeks were the first to identify objects that have no size, yet are able to build up the world around us through their interactions.
And as we are able to observe the world in tinier and tinier detail through microscopes of increasing power, it is natural to wonder what these objects are made of.
We believe we have found some of these objects: subatomic particles, or fundamental particles, which having no size can have no substructure. We are now seeking to explain the properties of these particles and working to show how these can be used to explain the contents of the universe.
By Ben P.
Uranium is the element having 92 protons in its nucleus with
typically 146 neutrons. It is the
largest naturally occurring element.
Like naturally occurring Thorium, uranium is radioactive and eventually
decays into radium and radon which are likewise radioactive. Both uranium and thorium decay through many series
of radioactive elements until they eventually become lead.
The top quark is the heaviest known elementary particle. It was discovered in 1995 by the CDF and DZERO experiments at the Fermilab Tevatron collider after a long hunt that had started almost two decades earlier: it took long because the top weighs as much as a whole silver atom, and producing this much matter in single particle-particle collisions is difficult: it requires collision energies that started to be available only in 1985, and the rarity of the production processes dictate collision rates that were delivered only in the early nineties.
General Atomics, which operates the DIII-D National Fusion Facility for the U.S. Department of Energy, and the Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have made a breakthrough in understanding how potentially damaging heat bursts inside a fusion reactor can be controlled.
The experiments with the DIII-D Fusion Facility, a tokamak in San Diego, represent a key step in predicting how to control heat bursts in future fusion facilities. Researchers have found that tiny magnetic fields applied to the device can create two distinct kinds of response, rather than just one response as previously thought.
Two photonic properties - spin and OAM1- have been teleported together for the first time ever. The breakthrough was achieved by Chaoyang Lu, Jian-Wei Pan and their team at University of Science and Technology of China, Hefei.
The team teleported the composite quantum states of a single photon encoded in both its spin and OAM1. For successful teleportation, three entangled pairs of photons were used.
The entangled pairs were created by the usual method of shining a strong UV pulsed laser on three non-linear crystals.
A research team from University of Leeds has figured out a way to kill cancer cells photothermally. They used Near-Infrared (NIR) to heat up gold nanotubes, and, a single-wavelength pulsed laser beam to rapidly increase the temperature near the nanotubes. This focussed, high-intensity heating kills the cancer cells.
A big advantage of the method is that NIR light has maximum penetration in the tissue without much harmful consequences. To minimize toxicity further, the gold nanotubes were coated with PSS - poly(sodium 4-styrenesulfonate).
The team is led by Steve Evans of the School of Physics and Astronomy.
An international team of physicists have been able to reconstruct the first ever 3-D image of individual virus particles by tweaking the X-ray diffraction technique of nanocrystallography1
Cleverly bypassing the tedious procedure of crystallizing individual particles, the researchers targeted the virus (Acanthamoeba polyphaga mimivirus) with high-energy pulses (70 fs duration) from an X-ray free electron laser. The X-rays scattered from the virus bodies, creating a 2D diffraction pattern.
Using 200 such different patterns and a mathematical algorithm to solve the problem of particle orientation, a single 3D electron density image was produced.