Citations with the tag: QUANTUM theory
Results 1 - 50
- Beating the uncertainty principle.
Baggott, J. // New Scientist; 2/15/92, Vol. 133 Issue 1808, p36
Discusses new experiments designed to test quantum theory's most widely accepted interpretation. Why problems with quantum theory arise; Description of experiments; Beliefs held by Niels Bohr and Werner Heisenberg. INSET: The amazing one-atom maser..
- Electrons file through the turnstile one by one.
Clery, D. // New Scientist; 4/4/92, Vol. 134 Issue 1815, p15
Reports that physicists have built a semiconductor chip in which they have observed single electrons jumping into a microscopic `box' within the structure. Look at individual quantum energy levels by measuring how electron movement affects capacitance of chips; Quantum mechanics predicts that...
- The Schrodinger equation and spin.
Boeyens, Jan C.A.; Kassman, Richard B. // South African Journal of Chemistry; Jun96, Vol. 49 Issue 1/2, p1
Presents an overview of the complete argument that defines spin as a non-relativistic concept. What is said about the quantum mechanical spin; What Levy-Leblond reveal about spin; Information on the Galilei group; Galilei invariance of the Schrodinger equation.
- Descrying the world in the wave function.
Maudlin, Tim // Monist; Jan97, Vol. 80 Issue 1, p3
Discusses quantum theory. Reference to work written by Wilfrid Sellars; Keys to understanding the problems confronting interpretations of quantum theory; Perspectives which the notion of the world is formed; Relationship between Scientific and Manifest Images.
- Uncertain decisions and the many-minds interpretation of...
Papineau, David // Monist; Jan97, Vol. 80 Issue 1, p97
Discusses quantum theory. Information on the `many-minds' interpretation of quantum theory; Difficulty facing questions on quantum theory; Philosophical approach to quantum theory.
- Identity, quantum mechanics and common sense.
Huggett, Nick // Monist; Jan97, Vol. 80 Issue 1, p118
Discusses how quantum mechanics (QM) has affronted out `common sense' notions of identity. Details on QM; Physical and philosophical issues associated with QM; Argument that QM is incompatible with individuals.
- Quantum double-talk makes messages cheaper.
Deutsch, David // New Scientist; 1/23/93, Vol. 137 Issue 1857, p14
Reports on research by Charles Bennett of IBM's Thomas J. Watson Research Center and Stephen Wiesner who have concluded that it is possible to use a photon to carry two bits of information instead of one when sending messages. Description of this scheme; Not technologically feasible yet.
- Letting the quantum cat out of the bag.
Hecht, Jeff // New Scientist; 10/21/95, Vol. 148 Issue 2000, p19
Reports that quantum mechanics' odd prediction that events do not have outcomes until they are measured has been verified by a new experiment conducted by University of Rochester's Leonard Mandel and staff. Past proofs of the prediction; Pair of photons polarized at right angles to one another,...
- Talking to the world next door.
Gribbin, John // New Scientist; 11/4/95, Vol. 148 Issue 2002, p20
Reports on the possibility of communicating with `parallel worlds' created by the quantum splitting of the Universe. Splitting of the world into two or more realities.
- Crossing the quantum frontier.
Buchanan, Mark // New Scientist; 04/26/97, Vol. 154 Issue 2079, p38
Focuses on advances made in the field of quantum physics. Differences between the quantum and classical worlds; Difficulty of applying quantum theories on the real world; Physicists involved in advancing the field of quantum physics.
- Where two worlds meet...
Brown, Julian // New Scientist; 5/18/96, Vol. 150 Issue 2030, p26
Studies various aspects of quantum theory. Link of theory to chaos; Mechanics of butterfly effect; Behavior of quantum systems; Differentiation of behavior of classical and quantum systems; Atomic absorption spectra; Correlation of spacing of Riemann numbers and energy levels.
- What's wrong with these elements of reality?
Mermin, N.D. // Physics Today; Jun90, Vol. 43 Issue 6, p9
Opinion. Describes an experiment which, the author says, gives the `spooky' Einstein-Podolsky-Rosen quantum correlations a powerful extension to gedanken decays that produce more than two particles.
- THE PHYSICS OF METAL CLUSTERS.
Cohen, Marvin L.; Knight, Walter D. // Physics Today; Dec90, Vol. 43 Issue 12, p42
Describes the Thompson-like model being used for metallic clusters using electron waves and a positive `jellium,' which can be justified from first-principles quantum theory. Description of `clusters' and `microclusters'; Trend toward miniaturization; History of shell models; Metallic character;...
- Perfect gibberish.
Zimmer, Carl; Anderson, Philip // Discover; Sep92, Vol. 13 Issue 9, p92
Explains how quantum physics rules can help cryptographers make an unbreakable code. Prototype quantum coding devices; Typical coding methods; Randomness of quantum reality; How uncertainty can be used in coding; Example; Use of polarized light;How quantum code is unbreakable; Possible...
- Uniform quantum-dot arrays formed by natural self-faceting on patterned substrates.
N�tzel, Richard; Niu, Zhichuan; Ramsteiner, Manfred; Sch�nherr, Hans-Peter; Tranpert, Achim; D�weritz, Lutz; Ploog, Klaus H. // Nature; 3/5/1998, Vol. 392 Issue 6671, p56
Reports on a method for improving size uniformity, while maintaining a high-density of quantum dots, that combines elements of both self-organization and patterning. The difficulty in obtaining high densities of structures in patterned growth; What the photoluminescence spectrum of the...
- Models of string theory and 2-D quantum gravity are solved exactly.
Khurana, A. // Physics Today; Apr90, Vol. 43 Issue 4, p17
Discusses how questions about enumeration of dissections of a planar surface have attracted the attention of mathematicians over the years. Looks at recently obtained exact solutions of simple models of quantum gravity in two dimensions and of simple string theories.
- Physics update.
Schewe, Phillip F. // Physics Today; Mar97, Vol. 50 Issue 3, p9
Discusses Q2, the quantum theory that holds the electromagnetic coupling constant. How the electron is being screened.
- Strange devices.
Perkowitz, Sidney // Sciences; Jan/Feb95, Vol. 35 Issue 1, p21
Deals with the world of quantum machines. Quantum laws' domination of minute devices; Propositions of the Quantum theory; Werner Heisenberg's uncertainty principle; Manufacture of quantum devices.
- Bridge over the quantum universe.
Perkowitz, Sidney // New Scientist; 10/10/92, Vol. 136 Issue 1842, p25
Focuses on quantum mechanics and the difficulties that lie in a process called decoherence. A look at the strangeness that lurks in the quantum mechanical world; Example of a situation described in quantum theory; Explanation of the process of decoherence. INSET: Interference and decoherence..
- Wake up to quantum coffee.
Baker, Howard // New Scientist; 03/15/97, Vol. 153 Issue 2073, p28
Reports on the use of quantum coexistence to build a generation of ultrafast computers. Fragility of quantum coexistence; Need for storage of bits using single particles rather than transistors; Tendency of superpositions to collapse; Application of nuclear magnetic resonance to quantum...
- Erratum: �The [sup 19]F�[sup 1]H coupling constants transmitted through covalent, hydrogen bond, and van der Waals interactions� [J. Chem. Phys. 115, 5498 (2001)].
Pecul, Magdalena; Sadlej, Joanna; Leszczynski, Jerzy // Journal of Chemical Physics; 1/22/2002, Vol. 116 Issue 4, p1748
Provides a corrected reprint of an article previously published in the 2001 issue, Volume 115 of the 'Journal of Chemical Physics.'
- Independently motivating the Kochen-Dieks modal interpretation of quantum mechanics.
Clifton, Rob // British Journal for the Philosophy of Science; Mar1995, Vol. 46 Issue 1, p33
Examines the Kochen-Dieks modal interpretation of quantum mechanics. Abandonment of the eigenstate-eigenvalue rule; Details of the Kochen-Dieks interpretation; Avoidance of contextualism and the problem of measurement.
- Quantum procrastination.
Greenland, P.T. // Nature; 6/5/1997, Vol. 387 Issue 6633, p548
Discusses present evidence for non-exponential decay, a clear prediction of quantum mechanics that has not been observed until recently as of June 5, 1997. Report by Wilkinson et al on page 575 of the same issue; The use of three accelerations in the experiment; Two features of the experiment.
- Quantum cryptography defies eavesdropping.
Collins, Graham P. // Physics Today; Nov92, Vol. 45 Issue 11, p21
Describes efforts of researchers to use the properties of quantum mechanics to encrypt information for secure transmission. Arthur Ekert's use of Bell's inequalities and the Einstein-Podolsky-Rosen effect to guarantee secure distribution of a cryptographic key; Work in field's beginnings in the...
- A tale of two kitties.
Gribbin, John // New Statesman & Society; 4/7/95, Vol. 8 Issue 347, p45
Attempts to explain some of the paradoxes in quantum mechanics. Phenomena of quantum mechanics; Relationships between energy, matter, space and time; Existence of publications which pointed out the absurdity of the Copenhagen interpretation of quantum mechanics.
- Quantum mechanics and frequentism: A reply to Ismael.
Strevens, Michael // British Journal for the Philosophy of Science; Dec96, Vol. 47 Issue 4, p575
Presents the author's reply to Jennan Ismael on the interpretation of the probabilities of quantum mechanics. Quantum mechanical description of the world; Introduction of probabilities in quantum mechanics in the form of some probabilistic law which governs the system.
- Copenhagen versus Bohmian interpretations of quantum theory.
Loewer, Barry // British Journal for the Philosophy of Science; Jun98, Vol. 49 Issue 2, p317
Presents a comparison between the Copenhagen and Bohmian interpretations of quantum theory. Information on the Copenhagen Interpretation of quantum mechanics (CQM); Propositions which interpret quantum mechanics; Details on the Bohmian Quantum Mechanics; Reference to the book `Quantum...
- Entanglement, decoherence and the quantum/classical boundary.
Haroche, Serge // Physics Today; Jul98, Vol. 51 Issue 7, p36
Focuses on quantum mechanics, with emphasis on the concepts of entanglement and decoherence. Details on an experiment conducted by Erwin Schrodinger; Information on some quantum optics experiments; Discussion on quantum weirdness; Fragility of quantum coherence.
- Particle physics and our everyday world.
Jensen, Pablo // Physics Today; Jul98, Vol. 51 Issue 7, p58
Opinion. Comments on particle physics as it relates to everyday life. Need for macroscopic concepts; Importance of quantum mechanics; Impact of developments in physics.
- 7-year (circaseptennian) patterns in psychology and biology? Comment on Verhulst and Onghena.
Cornelissen, Germaine; Sothern, Robert B.; Halberg, Francine; Halberg, Franz // Psychological Reports; Apr98, Vol. 82 Issue 2, p483
Studies the confirmation of an approximate 7-year birth pattern of the founders of quantum mechanics in inferential statistical terms by Verhulst and Onghena. Confirmation of a 7-year pattern on nonlinear rhythmometry; Description of the number of births by birth year of quantum fathers;...
- Quantum chaos.
Jensen, R.V. // Nature; 1/23/1992, Vol. 355 Issue 6358, p311
Ponders what the special properties of strongly perturbed quantum systems are when the corresponding classical mechanical systems exhibit chaotic behavior. Theoretical and experimental studies of highly excited atoms in strong magnetic fields andintense microwave fields which have revealed...
- Bringing order out of chaos.
Jensen, R.V. // Nature; 2/13/1992, Vol. 355 Issue 6361, p591
Comments on the thought that has been stimulated by the apparent contradiction that probabilistic quantum mechanics can be more regular and predictable than the corresponding deterministic, but potentially chaotic, classical mechanisms. First experimental test of the ideas invoked to resolve the...
- Stars at the quantum limit.
Jensen, R.V. // Nature; 11/5/1992, Vol. 360 Issue 6399, p15
Looks at an article by Chabrier, Ashcroft and DeWitt in the November 5, 1992 issue of `Nature,' that shows that quantum effects can affect the properties of matter even on the giant scale of stars. Convincing demonstration of the importance of quantum effects on the thermodynamics of the matter...
- Turning on quantum taps.
Barnett, Stephen M. // Nature; 3/11/1993, Vol. 362 Issue 6416, p113
Comments on a study by J. Ph. Poizat and P. Grangier which circumvents the sticky problem of the demolition of a quantum-mechanical observable by developing a method of delicately tapping off information on the state of a laser beam whilst leaving the signal unchanged. Two properties of the...
- Something from nothing.
Foot, C.J. // Nature; 3/18/1993, Vol. 362 Issue 6417, p206
Comments on a study by the group of Ed Hinds at Yale University measuring the remarkably delicate force sodium atoms experience as a result of the quantum electrodynamic (QED) fluctuations. Measurement of the Casimir-Polder effect; Description of the radiation field in QED; Measurement of cavity...
- Can quantum theory be understood?
Maddox, John // Nature; 2/11/1993, Vol. 361 Issue 6412, p493
Discusses the difficulties of understanding quantum theory. The Uncertainty Principle; William Hamilton; Question of the production of electron-pairs; Albert Einstein; Study by C.I. Sukenik et al; Casimir-Polder force; More.
- Uncertainty in quantum theory.
Maddox, John // Nature; 4/22/1993, Vol. 362 Issue 6422, p693
Comments that quantum mechanics is all the better since people have been busy bridging the gap between deterministic wave mechanics and the notion that everything is uncertain. Reasons for the general misunderstanding of quantum mechanics; Opportunities marked out by Feynman's triumph; Phase...
- Certainty from uncertainty.
Bennett, Charles H. // Nature; 4/22/1993, Vol. 362 Issue 6422, p694
Discusses the finding by physicists and computer scientists that quantum mechanics can serve as a source of certainty. Uncertainty principle of quantum mechanics; The extra power of quantum computer; Interference; Paper by David Deutsch of Oxford University and Richard Jozsa, now at Universite...
- Discrete charm of the photon.
Knight, Peter // Nature; 4/4/1996, Vol. 380 Issue 6573, p392
Ponders two papers which demonstrate the graininess of quanta and open up new methods of testing the predictions of basic quantum mechanics. The papers published in `Physical Review Letters'; Implications on the persistence of quantum coherence for mesoscopic systems.
- Trapped in mid-air.
Washburn, Sean // Nature; 8/13/1992, Vol. 358 Issue 6387, p537
Discusses the actions of a tennis ball tossed into a silo and comments on a study reported by Capasso and co-workers in the August 13, 1992 issue of `Nature.' Behavior of an electron in a specially designed semiconductor hetero-structure; Condensed matter science; Quantum mechanics; Creating...
- Observation of an electronic bound state above a potential well.
Capasso, Federico; Sirtori, Carlo // Nature; 8/13/1992, Vol. 358 Issue 6387, p565
Illustrates how bandgap engineering can be used to design almost arbitrary potentials so that wave functions and electronic properties can be tailored. Proposal by von Neumann and Wigner that certain spatially oscillating attractive potentials could support bound states at energies above the...
- Slit decision.
Capasso, Federico; Sirtori, Carlo // Nature; 5/6/1993, Vol. 363 Issue 6424, p18
States that the number of games that can be played to illustrate wave-particle duality is proliferating. Diffracting light through material slits (Young's slits); The diffraction of laser photons; The Bragg reflection; Additional information.
- Quantum optical tests of complementarity.
Scully, M.O.; Englert, B. // Nature; 5/9/1991, Vol. 351 Issue 6322, p111
Presents a review of new detectors that provide a way around the position-momentum uncertainty obstacle in atom interferometers. Gedanken experiments illustrating complementarity; A micromaser `welcher Weg' detector; Quantum eraser. INSET: Box 1 The Einstein-Bohr recoiling slit problem..
- Energy levels by path integration.
Maddox, John // Nature; 8/27/1992, Vol. 358 Issue 6389, p707
States that a gloss on Feynman's way of doing quantum mechanics will apparently help in calculating ground states. The work of Mark Kacs; Fenyman's account of quantum mechanics and charges that they were not mathematically rigorous; The connection between Kac's argument and parallel computers;...
- Electrons in artificial atoms.
Ashoori, R.C. // Nature; 2/1/1996, Vol. 379 Issue 6564, p413
Focuses on the results of two techniques that have affected the understanding of quantum dots. Allowing of the extraordinarily high-resolution of quantum dots; Use of semiconductor technology to grow gallium arsenide; Examination of the quantum energy level of a quantum dot containing one electron.
- Dying to know.
Chown, Marcus // New Scientist; 12/20/97&12/27/97, Vol. 156 Issue 2113/2114, p50
Looks at the complications associated with the interpretation of quantum theory, while describing the type of problems physicists encounter. Varying interpretations of the quantum theory; What is meant by the quantum theory; Benefits of conducting experiments; Myths and facts about the theory.
- Localization of relativistic particles.
Omnes, Roland // Journal of Mathematical Physics; Feb97, Vol. 38 Issue 2, p708
Studies the application of techniques to the localization of a photon in a given region of space in order to discuss localization experiments and also to extend the consistent history interpretation of quantum mechanics to relativistic properties. Problem of localization; Localizing a massless...
- Effectively Two-Dimensional Mechanism of Axion and Neutrino Bremsstrahlung in the Interaction of Electrons with Nuclei in a Magnetic Field.
Skobelev, V. V. // Physics of Atomic Nuclei; Aug2001, Vol. 64 Issue 8, p1481
Axion and neutrino bremsstrahlung from electrons in the processes e (Ze) ? e (Ze) a (?&?macr;) is considered within the proposed two-dimensional covariant method for calculating Feynman diagrams in an external magnetic field. General expressions for squared matrix elements, as well as for the...
- Comment on ��Comparison of positive flux operators for transition state theory using a solvable model�� [J. Chem. Phys. 104, 7015 (1996)].
Miller, William H. // Journal of Chemical Physics; 10/8/96, Vol. 105 Issue 14, p6090
The Weyl definition of the positive component of the flux operator is discussed. Specifically, it is noted that the imaginary part of the operator makes no contribution to the quantum mechanical transition state theory rate constant, and this is why it was omitted in previous work on the topic....
- Quantum statistical mechanics via the recursive residue generation method.
Friesner, Richard A.; Wyatt, Robert E. // Journal of Chemical Physics; 2/15/85, Vol. 82 Issue 4, p1973
Using the recursive residue generation method (RRGM), it is shown how Green�s function matrix elements calculated in large basis sets (N>103) can be utilized to obtain controlled approximations to average values, correlation functions, and power spectra in multimode anharmonic systems....