A combined team of physicists from the University of Sussex and the National Physical Laboratory, both in the U.K., has been designing experiments to identify ultra-light dark matter particles. In their paper published in the open-access New Journal of Physics, the group describes how they are attempting to use the high precision of atomic clocks to detect ultra-light dark matter particle “kicks” that would lead to time variations and, in so doing, would show evidence of dark matter.
Currently, dark matter is not something that has been shown to exist—instead it is more of a placeholder that has been created to explain observations of deviations from the Standard Model of physics—like certain gravitational effects on galaxies. Since its development as a theory back in the early 1930s, physicists around the world have been developing theories and experiments to prove that it exists.
Sadly, despite a lot of time and effort, no such proof has been found. In this new effort, the team in the U.K. is working on a novel way to add credence to dark matter theories—using atomic clocks to detect ultra-light dark matter particles.
Scientists have been able to observe a common interaction in quantum chemistry for the first time, by using a quantum computer to shadow the process at a speed 100 billion times slower than normal.
Known as a conical intersection, the interactions have long been known about, but are usually over in mere femtoseconds – quadrillionths of a second – making direct observations impossible to carry out.
Not all of the material around us is stable. Some materials may undergo radioactive decay to form more stable isotopes. Scientists have now observed a new decay mode for the first time. In this decay, a lighter form of oxygen, oxygen-13 (with eight protons and five neutrons), decays by breaking into three helium nuclei (an atom without the surrounding electrons), a proton, and a positron (the antimatter version of an electron).
Scientists observed this decay by watching a single nucleus break apart and measuring the breakup products. The study is published in the journal Physical Review Letters.
Scientists have previously observed interesting modes of radioactive decay following the process called beta-plus decay. This is where a proton turns into a neutron and emits some of the produced energy by emitting a positron and an antineutrino. After this initial beta-decay, the resulting nucleus can have enough energy to boil off extra particles and make itself more stable.
These all-purpose, desktop machines can reproduce a seemingly infinite variety of items. In fact, they are like miniature factories. In appearance, they resemble a combined washing machine/microwave oven. Raw materials are purchased separately and can be loaded in solid, liquid or powder form. An interior compartment is accessed via a small hatch, where objects are constructed atom-by-atom. The process takes a matter of minutes and the assembled items can be used immediately. New schematics can be accessed from the web and programmed into the machine.
I did not create this animation video and i do not gain any profit from it. This is for educational purposes only.
A molecular assembler, as defined by K. Eric Drexler, is a “proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision”. A molecular assembler is a kind of molecular machine. Some biological molecules such as ribosomes fit this definition. This is because they receive instructions from messenger RNA and then assemble specific sequences of amino acids to construct protein molecules. However, the term “molecular assembler” usually refers to theoretical human-made devices.
Beginning in 2007, the British Engineering and Physical Sciences Research Council has funded development of ribosome-like molecular assemblers. Clearly, molecular assemblers are possible in this limited sense. A technology roadmap project, led by the Battelle Memorial Institute and hosted by several U.S. National Laboratories has explored a range of atomically precise fabrication technologies, including both early-generation and longer-term prospects for programmable molecular assembly; the report was released in December, 2007. In 2008 the Engineering and Physical Sciences Research Council provided funding of 1.5 million pounds over six years for research working towards mechanized mechanosynthesis, in partnership with the Institute for Molecular Manufacturing, amongst others. Likewise, the term “molecular assembler” has been used in science fiction and popular culture to refer to a wide range of fantastic atom-manipulating nanomachines, many of which may be physically impossible in reality. Much of the controversy regarding “molecular assemblers” results from the confusion in the use of the name for both technical concepts and popular fantasies. In 1992, Drexler introduced the related but better-understood term “molecular manufacturing”, which he defined as the programmed “chemical synthesis of complex structures by mechanically positioning reactive molecules, not by manipulating individual atoms”.This article mostly discusses “molecular assemblers” in the popular sense. These include hypothetical machines that manipulate individual atoms and machines with organism-like self-replicating abilities, mobility, ability to consume food, and so forth. These are quite different from devices that merely (as defined above) “guide chemical reactions by positioning reactive molecules with atomic precision”. Because synthetic molecular assemblers have never been constructed and because of the confusion regarding the meaning of the term, there has been much controversy as to whether “molecular assemblers” are possible or simply science fiction. Confusion and controversy also stem from their classification as nanotechnology, which is an active area of laboratory research which has already been applied to the production of real products; however, there had been, until recently, no research efforts into the actual construction of “molecular assemblers”. Nonetheless, a 2013 paper by David Leigh’s group, published in the journal Science, details a new method of synthesizing a peptide in a sequence-specific manner by using an artificial molecular machine that is guided by a molecular strand. This functions in the same way as a ribosome building proteins by assembling amino acids according to a messenger RNA blueprint. The structure of the machine is based on a rotaxane, which is a molecular ring sliding along a molecular axle. The ring carries a thiolate group which removes amino acids in sequence from the axle, transferring them to a peptide assembly site. In 2018, the same group published a more advanced version of this concept in which the molecular ring shuttles along a polymeric track to assemble an oligopeptide that can fold into a α-helix that can perform the enantioselective epoxidation of a chalcone derivative (in a way reminiscent to the ribosome assembling an enzyme). In another paper published in Science in March 2015, chemists at the University of Illinois report a platform that automates the synthesis of 14 classes of small molecules, with thousands of compatible building blocks. In 2017 David Leigh’s group reported a molecular robot that could be programmed to construct any one of four different stereoisomers of a molecular product by using a nanomechanical robotic arm to move a molecular substrate between different reactive sites of an artificial molecular machine. An accompanying News and Views article, titled ‘A molecular assembler’, outlined the operation of the molecular robot as effectively a prototypical molecular assembler.
For the first time, physicists from Finland and the United States have observed a special kind of magnetic monopole called an “Alice Ring.”
A team of researchers from the United States and Finland have observed enigmatic “Alice Rings” in super cold gas for the first time. A strange kind of circular magnetic monopoles, “Alice Rings” are a kind of quantum phenomenon that has, until now, only existed in theory. Various forces and particles can arise from the quantum machinery, theoretically including monopoles.
A new symmetry-based classification could help researchers describe open, many-body quantum systems that display quantum chaos.
The quest for understanding quantum systems of many particles—and the exotic phenomena they display—fascinates theorists and experimentalists alike, but it’s one with many hurdles. The number of the system’s quantum states increases exponentially with size; these states are hard to prepare, probe, and characterize in experiments, and interactions with the environment “open” the system, further increasing the number of states to consider. As a result, open, many-body quantum systems remain a frontier of exploration in physics, for which researchers haven’t developed a systematic theoretical framework. A new study by Kohei Kawabata of Princeton University and colleagues has taken an important step toward developing such a general framework by offering a complete classification of these systems based on symmetry principles [1] (Fig. 1).
The observation of elusive, exotic particles is the key objective of countless studies, as it could open new avenues for research, while also improving present knowledge of the matter contained in the universe and its underlying physics. The quark model, a theoretical model introduced in 1964, predicted the existence of elementary subatomic particles known as quarks in their different configurations.
Quarks and antiquarks (the anti-matter equivalent of quarks) are predicted to be constituents of various subatomic particles. These include “conventional” particles, such as mesons and baryons, as well as more complex particles made up of four or five quarks (i.e., tetraquarks and pentaquarks, respectively).
The Large Hadron Collider beauty (LHCb) experiment, a research effort involving a large group of researchers at different institutes worldwide, has been trying to observe some of these fascinating particles for over a decade, using data collected at CERN’s LHC particle collider in Switzerland. In a recent paper published in Physical Review Letters, they reported the very first observation of a doubly charged tetraquark and its neutral partner.
The mysterious phenomenon that Einstein once described as “spooky action at a distance” was seen as a wavefunction between two entangled photons.
Quantum physics, the realm of science that describes the Universe at the smallest scales, is known for its counter-intuitive phenomena that seem to defy every law of physics on an everyday scale.
Arguably none of the aspects of quantum physics are as surprising or as troubling as entanglement, the idea that two particles can be connected in such a way that a change to one is instantly reflected in the other, even if the two particles are at opposite sides of the Universe. It’s the word “instantly” that troubled Albert Einstein enough to describe entanglement as “spooky action at a distance”.
