DIAMOND STAR

Twinkling in the sky is a diamond star of 10 billion trillion trillion carats, astronomers have discovered. The cosmic diamond is a chunk of crystallised carbon, 4,000 km across, some 50 light-years from the Earth in the constellation Centaurus.It's the compressed heart of an old star that was once bright like our Sun but has since faded and shrunk.Astronomers have decided to call the star "Lucy" after the Beatles song, Lucy in the Sky with Diamonds.Twinkle twinkle"You would need a jeweller's loupe the size of the Sun to grade this diamond," says astronomer Travis Metcalfe, of the Harvard-Smithsonian Center for Astrophysics, who led the team of researchers that discovered it.The diamond star completely outclasses the largest diamond on Earth, the 546-carat Golden Jubilee which was cut from a stone brought out of the Premier mine in South Africa.The huge cosmic diamond - technically known as BPM 37093 - is actually a crystallised white dwarf. A white dwarf is the hot core of a star, left over after the star uses up its nuclear fuel and dies. It is made mostly of carbon.For more than four decades, astronomers have thought that the interiors of white dwarfs crystallised, but obtaining direct evidence became possible only recently.The white dwarf is not only radiant but also rings like a gigantic gong, undergoing constant pulsations."By measuring those pulsations, we were able to study the hidden interior of the white dwarf, just like seismograph measurements of earthquakes allow geologists to study the interior of the Earth."We figured out that the carbon interior of this white dwarf has solidified to form the galaxy's largest diamond," says Metcalfe.Astronomers expect our Sun will become a white dwarf when it dies 5 billion years from now. Some two billion years after that, the Sun's ember core will crystallise as well, leaving a giant diamond in the centre of the solar system."Our Sun will become a diamond that truly is forever," says Metcalfe.

QUANTUM

Quantum tunnelling (or tunneling) is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. Consider rolling a ball up a hill. If the ball is not given enough velocity, then it will not roll over the hill. This makes sense classically. But in quantum mechanics, objects do not behave like classical objects, such as balls, do. On a quantum scale, objects exhibit wavelike behavior. For a quantum particle moving against a potential hill, the wave function describing the particle can extend to the other side of the hill. This wave represents the probability of finding the particle in a certain location, meaning that the particle has the possibility of being detected on the other side of the hill. This behavior is called tunneling; it is as if the particle has 'dug' through the potential hill.Wave/particle duality is a quantum phenomenon usually confined to photons, electrons, protons, and other ultra-tiny objects. Quantum mechanics shows that such objects sometimes behave like particles, sometimes behave like waves, and sometimes like a little of both.
All objects exhibit wave/particle duality to some extent, but the larger the object the harder it is to observe. Even individual molecules are often too large to show the quantum mechanical behavior.
Now physicists at the Université de Paris have demonstrated wave/particle duality with a droplet made of trillions of molecules.
The experiment involved an oil droplet bouncing on the surface of an agitated layer of oil. The droplet created waves on the surface, which in turn affected the motion of the droplet. As a result, the droplet and waves formed a single entity that consisted of a hybrid of wave-like and particle-like characteristics.
When the wave/droplet bounced its way through a slit, the waves allowed it to interfere with its own motion, much as a single photon can interfere with itself via quantum mechanics.
Although the wave/droplet is clearly a denizen of the classical world, the experiment provides a clever analogue of quantum weirdness at a scale that is much easier to study and visualize than is typical of many true quantum experiments.Quantum teleportation has been experimentally demonstrated by physicists at the University of Innsbruck. First proposed in 1993 by Charles Bennett of IBM and his colleagues, quantum teleportation allows physicists to take a photon (or any other quantum-scale particle, such as an atom), and transfer its properties (such as its polarization) to another photon -- even if the two photons are on opposite sides of the galaxy.
Note that this scheme transports the particle's properties to the remote location and not the particle itself. And as with Star Trek's Captain Kirk, whose body is destroyed at the teleporter and reconstructed at his destination, the state of the original photon must be destroyed to create an exact reconstruction at the other end.
In the Innsbruck experiment, the researchers create a pair of photons A and B that are quantum mechanically "entangled": the polarization of each photon is in a fuzzy, undetermined state, yet the two photons have a precisely defined interrelationship. If one photon is later measured to have, say, a horizontal polarization, then the other photon must "collapse" into the complementary state of vertical polarization.
In the experiment, one of the entangled photons A arrives at an optical device at the exact time as a "message" photon M whose polarization state is to be teleported. These two photons enter a device where they become indistinguishable, thus effacing our knowledge of M's polarization (the equivalent of destroying Kirk).
What the researchers have verified is that by ensuring that M's polarization is complementary to A's, then B's polarization would now have to assume the same value as M's. In other words, although M and B have never been in contact, B has been imprinted with M's polarization value, across the whole galaxy, instantaneously.
This does not mean that faster-than-light information transfer has occurred. The people at the sending station must still convey the fact that teleportation had been successful by making a phone call or using some other light-speed or sub-light-speed means of communication. While physicists don't foresee the possibility of teleporting large-scale objects like humans, this scheme will have uses in quantum computing and cryptography.