Storing quantum information in designer molecules could hold advantages over atoms, ions, and other kinds of qubits
Category: particle physics
Unusual nonlinear thermoelectric effect appears in chiral tellurium, confirming theoretical predictions
An unusual thermoelectric effect has been observed in the semiconductor tellurium by RIKEN physicists for the first time. This demonstration points to the potential of similar materials to be used in applications such as energy harvesting and advanced heat management.
Thermoelectric materials can convert electricity into heat and vice versa. For most of them, doubling the voltage across them will double the heat they produce. But for some special thermoelectric materials, there is a nonlinear relationship between voltage and heat. Such nonlinear thermoelectric materials are useful for applications that require heat to flow in one direction and for generating electricity from thermal fluctuations.
Some theoretical calculations have predicted that even more exotic nonlinear thermoelectric effects will occur in materials where the atoms or molecules have a chiral arrangement. But they hadn’t been observed in the lab—until now.
Crystals of space and time: A structural phenomenon that may collapse into tiny black holes
A team from Vienna and Frankfurt has found a formula describing a strange phenomenon: Space and time can form a kind of “crystal” that may turn into a black hole. The results are described in Physical Review Letters.
Alongside the famous gigantic black holes, physics also allows for microscopic versions. They emerge from so-called critical states, when spacetime organizes itself into a regular, crystal-like structure during a process known as critical collapse. A team from Goethe University Frankfurt and TU Wien has now succeeded, for the first time, in describing this phenomenon with an exact mathematical formula using an unusual mathematical trick.
Black holes usually form in spectacular events, such as the death of a massive star. But in theory, arbitrarily small black holes are also possible: tiny microscopic objects that can emerge from special critical states after the slightest addition of energy. Such states may have existed shortly after the Big Bang, when the universe was still a chaotic mixture of particles, potentially giving rise to so-called primordial black holes.
What if the direction of a magnet could shape the building blocks of life?
In a new discovery, researchers from the Hebrew University of Jerusalem and the Weizmann Institute of Science have found that something in the direction of a magnetic field can influence how molecules of life behave at the most fundamental level and how early chemical processes linked to life may have unfolded.
The study, published in Chem and led by Prof. Yossi Paltiel (Hebrew University) and Prof. Michal Sharon (Weizmann Institute), shows that tiny differences between atoms (different isotopes) can lead to measurable changes in molecular behavior when combined with an invisible quantum property known as electron spin. Separation of the different isotopes can be achieved by magnetic surfaces.
At the center of the story is L-methionine, an amino acid, a basic building block of life. Like other biological molecules, methionine has a specific “handedness,” meaning it exists in a form that is not identical to its mirror image. This property, called chirality, is a mystery: why did nature choose one “hand” over the other?
The complete evolution of spin glass from order to chaos
How come our universe is full of disorder, when all elementary particles appear to follow strictly ordered laws of physics? And are there organizing principles behind disorder and apparent chaos?
One avenue of studying these fundamental questions is through an assembly of spins: the quantum property that makes electrons behave like tiny bar magnets, with a preferred orientation of either up or down. Neighboring spins align either in parallel (up-up) or antiparallel (up-down-up-down), as in ferromagnets and antiferromagnets, respectively. This simple ruleset makes spin systems very attractive for studying the emergence of order.
However, while the theory of spin is well-established, creating the material conditions for observing spin disorder has proven notoriously elusive. While physicists have been able to create exotic materials that exhibit spin disorder, tracing the evolution from order to disorder within materials has been challenged by the lack of a clean starting point.
Physicists confirm ‘negative time’ is real by asking the atoms themselves
A new experiment confirms that photons passing through a cloud of atoms can spend a negative amount of time there, and the atoms themselves are the ones saying so.
Researchers measure giant light-conversion effect in chiral carbon nanotubes
A sheet of twisted carbon nanotubes has revealed a hidden talent scientists suspected for decades but had never managed to measure.
Researchers at Rice University have created large, highly ordered films of chiral carbon nanotubes (CNTs), hollow cylinders of carbon atoms with either a left-or a right-handed twist. Measurements showed the crystalline films can convert the color of light at a rate two to three orders of magnitude greater than conventional materials.
The findings, reported in a study published in ACS Nano, confirm a long-standing theoretical prediction and point toward a future in which ultrathin carbon nanotube films could help power faster optical communications, flexible photonic chips and light-based computing systems that today exist mostly as prototypes.