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Category: quantum physics – Page 707

Is teleportation possible? Yes, in the quantum world

“Beam me up” is one of the most famous catchphrases from the Star Trek series. It is the command issued when a character wishes to teleport from a remote location back to the Starship Enterprise.

While human teleportation exists only in , teleportation is possible in the subatomic world of quantum mechanics—albeit not in the way typically depicted on TV. In the , teleportation involves the transportation of information, rather than the transportation of matter.

Last year scientists confirmed that information could be passed between photons on even when the photons were not physically linked.

Quantum rings in the grip of laser light

Ultracold atoms trapped in appropriately prepared optical traps can arrange themselves in surprisingly complex, hitherto unobserved structures, according to scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences in Cracow. In line with their most recent predictions, matter in optical lattices should form tensile and inhomogeneous quantum rings in a controlled manner.

An optical lattice is a structure built of light, i.e. . Lasers play a key role in the construction of such lattices. Each laser generates an electromagnetic wave with strictly defined, constant parameters which can be almost arbitrary modified. When the laser beams are matched properly, it is possible to create a lattice with well known properties. By overlapping of waves, the minima of potential can be obtained, whose arrangement enables simulation of the systems and models well-known from solid state . The advantage of such prepared systems is the relatively simple way to modify positions of these minima, what in practice means the possibility of preparing various type of lattices.

“If we introduce appropriately selected atoms into an area of space that has been prepared in this way, they will congregate in the locations of potential minima. However, there is an important condition: the atoms must be cooled to ultra-low temperatures. Only then will their energy be small enough not to break out of the subtle prepared trap,” explains Dr. Andrzej Ptok from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow.

Simultaneous nodal superconductivity and broken time-reversal symmetry in CaPtAs

In the vast majority of superconducting materials, Cooper pairs have what is known as even parity, which essentially means that their wave function does not change when electrons swap spatial coordinates. Conversely, some unconventional superconductors have been found to contain odd-parity Cooper pairs. This quality makes these unconventional materials particularly promising for quantum computing applications.

Past studies have predicted that noncentrosymmetric , which have a crystal structure with no center of inversion, could exhibit unique and unusual properties. In recent years, noncentrosymmetric superconductors have become a popular topic of research due to the structure of the Cooper pairs contained within them, which have a mixture of odd and even parity.

CaPtAs is a new noncentrosymmetric superconductor discovered by researchers at Zhejiang University. Together with scientists at the Paul Scherrer Institut and other institutes worldwide, these researchers have recently carried out a study investigating in this compound. Their paper, published in Physical Review Letters, offers evidence that in its superconducting state, CaPtAs simultaneously exhibits both nodal superconductivity and broken time-reversal symmetry (TRS).

Nano-motor of just 16 atoms runs at the boundary of quantum physics

Researchers at Empa and EPFL have created one of the smallest motors ever made. It’s composed of just 16 atoms, and at that tiny size it seems to function right on the boundary between classical physics and the spooky quantum realm.

Like its macroscopic counterparts, this mini motor is made up of a moving part (the rotor) and a fixed part (the stator). The stator in this case is a cluster of six palladium atoms and six gallium atoms arranged in a rough triangular shape. Meanwhile, the rotor is a four-atom acetylene molecule, which rotates on the surface of the stator. The whole machine measures less than a nanometer wide.

The molecular motor can be powered by either thermal or electrical energy, although the latter was found to be much more useful. At room temperature, for example, the rotor was found to rotate back and forth at random. But when an electric current was applied using an electron scanning microscope, the rotor would spin in one direction with a 99-percent stability.

The smallest motor in the world

A research team from Empa and EPFL has developed a molecular motor which consists of only 16 atoms and rotates reliably in one direction. It could allow energy harvesting at the atomic level. The special feature of the motor is that it moves exactly at the boundary between classical motion and quantum tunneling — and has revealed puzzling phenomena to researchers in the quantum realm.

The smallest motor in the world—consisting of just 16 atoms: this was developed by a team of researchers from Empa and EPFL. “This brings us close to the ultimate size limit for molecular motors,” explains Oliver Gröning, head of the Functional Surfaces Research Group at Empa. The motor measures less than one nanometer—in other words it is around 100,000 times smaller than the diameter of a human hair.

In principle, a molecular machine functions in a similar way to its counterpart in the macro world: it converts energy into a directed movement. Such molecular motors also exist in nature—for example in the form of myosins. Myosins are that play an important role in living organisms in the contraction of muscles and the transport of other molecules between cells.