The 'molecular octopus': A little brother of 'Schroedinger’s cat' For the first time, the quantum behaviour of molecules consisting of more than 400 atoms was demonstrated by quantum physicists based at the University of Vienna in collaboration with chemists from Basel and Delaware. The international and interdisciplinary team of scientists has set a new record in the verification of the quantum properties of nanoparticles. In addition, an important aspect of the famous thought experiment known as 'Schroedinger's cat' is probed. However, due to the particular shape of the chosen molecules the reported experiment could be more fittingly called 'molecular octopus'. The researchers report their findings in Nature Communications. 'Schroedinger's cat': simultaneously dead and alive? Since the beginning of the 20th century, quantum mechanics has been a pillar of modern physics. 'Superposition' demonstrated for larger and larger molecules In quantum physics, the propagation of massive particles is described by means of matter waves.
A new record. #87: A Superfast Magnetic Shift | Earth Science. Every 200,000 years or so, the earth’s poles trade places. Typically it takes several thousand years. But when geologists Scott Bogue of Occidental College and Jonathan Glen of the U.S. Geological Survey examined 15-million-year-old Nevada lava, they found evidence that the planet’s magnetic field shifted several thousand times faster than normal at least once. When lava cools, it locks away a record of the earth’s magnetic field. Examining lavas that cooled in two consecutive years, Bogue and Glen found the field swung 53 degrees from east to north, about 1 degree a week. Bogue thinks the quick shift took place near the end of a millennia-long polarity reversal, when a slow magnetic drift accelerated dramatically for reasons unexplained. Further study could help geologists understand the turbulent motion of the earth’s liquid core, which generates the magnetic field and may initiate its flips.
Quantum tunnelling. Quantum mechanical phenomenon In physics, quantum tunnelling, barrier penetration, or simply tunnelling is a quantum mechanical phenomenon in which an object such as an electron or atom passes through a potential energy barrier that, according to classical mechanics, should not be passable due to the object not having sufficient energy to pass or surmount the barrier. Tunneling is a consequence of the wave nature of matter, where the quantum wave function describes the state of a particle or other physical system, and wave equations such as the Schrödinger equation describe their behavior. The probability of transmission of a wave packet through a barrier decreases exponentially with the barrier height, the barrier width, and the tunneling particle's mass, so tunneling is seen most prominently in low-mass particles such as electrons or protons tunneling through microscopically narrow barriers.
The effect was predicted in the early 20th century. Introduction to the concept[edit] or where . Many-worlds interpretation. The quantum-mechanical "Schrödinger's cat" paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point; the cat is both alive and dead, even before the box is opened, but the "alive" and "dead" cats are in different branches of the universe, both of which are equally real, but which do not interact with each other.[1] The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse.
Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In lay terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes. Outline[edit] Interpreting wavefunction collapse[edit] Probability[edit] where. Unexpected hanging paradox. The unexpected hanging paradox, hangman paradox, unexpected exam paradox, surprise test paradox or prediction paradox is a paradox about a person's expectations about the timing of a future event (e.g. a prisoner's hanging, or a school test) which he is told will occur at an unexpected time. Despite significant academic interest, there is no consensus on its precise nature and consequently a final 'correct' resolution has not yet been established.[1] One approach, offered by the logical school of thought, suggests that the problem arises in a self-contradictory self-referencing statement at the heart of the judge's sentence.
Another approach, offered by the epistemological school of thought, suggests the unexpected hanging paradox is an example of an epistemic paradox because it turns on our concept of knowledge.[2] Even though it is apparently simple, the paradox's underlying complexities have even led to it being called a "significant problem" for philosophy.[3] Some authors[who?] Is Nuclear Power Safe? - Nuclear Power Safety. Myth No. 1 Nuclear Power Isn't a Safe Solution In a recent national poll, 72 percent of respondents expressed concern about potential accidents at nuclear power plants. Some opinion-makers have encouraged this trepidation: Steven Cohen, executive director of Columbia University's Earth Institute, has called nuclear power "dangerous, complicated and politically controversial.
" During the first six decades of the nuclear age, however, fewer than 100 people have died as a result of nuclear power plant accidents. Power sources such as coal and petroleum might seem safer than nuclear, but statistically they're a lot deadlier. INL nuclear lab's deputy associate director, Kathryn McCarthy, thinks the industry can overcome its stigma. Negative probability. The probability of the outcome of an experiment is never negative, but quasiprobability distributions can be defined that allow a negative probability for some events. These distributions may apply to unobservable events or conditional probabilities. Physics[edit] In 1942, Paul Dirac wrote a paper "The Physical Interpretation of Quantum Mechanics"[1] where he introduced the concept of negative energies and negative probabilities: "Negative energies and probabilities should not be considered as nonsense.
They are well-defined concepts mathematically, like a negative of money. " Mark Burgin gives another example: "Let us consider the situation when an attentive person A with the high knowledge of English writes some text T. Negative probabilities have later been suggested to solve several problems and paradoxes.[3] Half-coins provide simple examples for negative probabilities.
In Convolution quotients of nonnegative definite functions[5] and Algebraic Probability Theory [6] Imre Z. One-electron universe. The one-electron universe hypothesis, commonly associated with Richard Feynman when he mentioned it in his Nobel lecture,[1] postulates that there exists only a single electron in the universe, propagating through space and time in such a way as to appear in many places simultaneously.
History[edit] Feynman's thesis advisor, John Wheeler, proposed the hypothesis in a telephone call to Feynman in the spring of 1940. He excitedly claimed to have developed a neat explanation of the quantum mechanical indistinguishability of electrons: As a by-product of this same view, I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, "Feynman, I know why all electrons have the same charge and the same mass" "Why? " "Because, they are all the same electron!
" References[edit] External links[edit] Jagdish Mehra, The Beat of a Different Drum, The Life and Science of Richard Feynman, Oxford, 1994, pages 113–115.