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Topic: Bell test experiments


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  Alexander Graham Bell - MSN Encarta
Bell was born on March 3, 1847, in Edinburgh, Scotland, and educated at the universities of Edinburgh and London.
His experiments with his assistant Thomas Watson finally proved successful on March 10, 1876, when he transmitted: “Watson, come here; I want you.” Subsequent demonstrations, particularly one at the 1876 Centennial Exposition in Philadelphia, Pennsylvania, introduced the telephone to the world and led to the organization of the Bell Telephone Company in 1877.
Bell was one of the cofounders of the National Geographic Society, and he served as its president from 1896 to 1904.
encarta.msn.com /encyclopedia_761568424/Bell_Alexander_Graham.html   (574 words)

  
 Bell test experiments - Wikipedia, the free encyclopedia   (Site not responding. Last check: 2007-10-22)
The term "Bell inequality" can mean any one of a number of inequalities — in practice, in real experiments, the CHSH or CH74 inequality, not the original one derived by John Bell.
In practice most actual experiments have used light, assumed to be emitted in the form of particle-like photons (produced by atomic cascade or Spontaneous parametric down conversion), rather than the atoms that Bell originally had in mind.
This was the first actual Bell test, using Freedman's inequality, a variant on the CH74 inequality.
en.wikipedia.org /wiki/Bell_test_experiments   (1594 words)

  
 Bell_John biography
John Bell's great achievement was that during the 1960s he was able to breathe new and exciting life into the foundations of quantum theory, a topic seemingly exhausted by the outcome of the Bohr-Einstein debate thirty years earlier, and ignored by virtually all those who used quantum theory in the intervening period.
Bell was able to show that discussion of such concepts as 'realism', 'determinism' and 'locality' could be sharpened into a rigorous mathematical statement, 'Bell's inequality', which is capable of experimental test.
Bell then spent a year as a technician in the Physics Department at Queen's University Belfast, where the senior members of staff in the Department, Professor Karl Emeleus and Dr Robert Sloane, were exceptionally helpful, lending Bell books and allowing him to attend the first year lectures.
www-groups.dcs.st-and.ac.uk /~history/Biographies/Bell_John.html   (2975 words)

  
 the Electronic Bell Jar - Plasma Experiments
Plasma Diagnostic Experiment - Measurement of plasma electron temperature and electron density by a single Langmuir probe using the OA4-G. Observation of the plasma electron frequency using the 866-A. Investigation of the decaying plasma using the 866-A. The second experiment, as adapted by Jones, is diagrammed in Figure 1.
In the experiment, a discharge is struck between the anode and cathode.
Experiments in a solenoidal field are described in Behavior of a Single Langmuir Probe in a Magnetic Field (J.T. Pytlinski, H.J. Donnert and I. Alexeff, December 1978).
www.belljar.net /plasma.htm   (2373 words)

  
 ||++ IEEE STUDENTS BRANCH - SSEC, INDIA ++|| :: Explorer Watch Home Page ::
Bell reasoned that it would be possible to pick up all the sounds of the human voice using an adaptation of the "harmonic telegraph." In 1875, along with his assistant Thomas A. Watson, Bell constructed instruments that transmitted recognizable voice-like sounds.
Bell's first telephone patent was granted on March 7, 1876.
Bell was granted 18 patents in his name, and 12 he shared with collaborators.
www.ewh.ieee.org /sb/srisairamec/stuff_center/bell.htm   (280 words)

  
 Bell Test
Let the students experiment with this, create and play songs until you are convinced they can tell the difference between a higher pitch in a tense string and a lower pitch in a looser one.
Ring one of the bells and the students write (by identifying the sound) which bell, A, B, C or D is being rung as number one in the test.
Before ringing the last bell, ask the students to use the process of elimination to decide what the last bell must be if all the others have been rung.
web2.airmail.net /kboyle/Belltest.htm   (636 words)

  
 Mike Gorman: Bell's Path to the Telephone--Bell's Liquid Variable Resistor Experiments, March 8-10
Bell began with the experiment shown in the slot diagram; one tine of the vibrating fork was placed in the water..
Returning to Bell's experiments, once he had established that increasing the size of the contact on the conducting wire would improve transmission, he decided to increase the size of the vibrating contact; to do this, he substituted a bell for the tuni ng fork.
Bell here has used a needle for the vibrating contact and a long, flat ribbon for th e other, thereby minimizing the area of the former with respect to the latter.
www.iath.virginia.edu /albell/blvrem.2.html   (1256 words)

  
 Bell's Theorem (Stanford Encyclopedia of Philosophy)
In the experiment proposed by CHSH the measurements are polarization analyses with the transmission axis of analyzer I oriented at angles a and a′, and the transmission axis of analyzer II oriented at angles b and b′.
The first experiment using polarization analyzers with two exit channels, thus realizing the theoretical scheme in the third step of the argument for Bell's Theorem in Section 2, was performed in the early 1980s with cascade photons from laser-excited calcium atoms by Aspect, Grangier, and Roger (1982).
In experiments using photon pairs from a cascade, as most of the early Bell tests were, it can happen that the second transition occurs without the first step in the cascade, thus producing a single photon without a partner.
plato.stanford.edu /entries/bell-theorem   (12693 words)

  
 Quantum Reflections - ed. John Ellis and Daniele Amati
Bell and his work are, however, the unifying thread behind the pieces, and the collection as a whole does stand as a neat Festschrift for the great scientist.
The contributions range from Mary Bell's useful Biographical notes and Roman Jackiw's remembrance of the man to a variety of considerations of Bell's work, considerations of the consequences of his theories (specifically Bell's Theorem and Bell's Inequality), and descriptions of experiments that test Bell's theories.
In their contribution, John Bell and the moral aspect of quantum mechanics, Kurt Gottfried and N. David Mermin state that "Bell has had the greatest impact on the interpretation of quantum mechanics of anyone since the 1920s"; few would argue that this is not true.
www.complete-review.com /reviews/belljs/qreflect.htm   (960 words)

  
 Classical Interpretation of EPR- Bell Test Photon Correlation Experiments   (Site not responding. Last check: 2007-10-22)
Many experiments have been performed in the past in order to answer the question if Quantum Mechanics is complete or if its statistical and indeterministic nature is only an apparent one and some 'hidden variables' exist that would in principle enable a deterministic description.
All experiments are claimed to rule out the existence of Hidden Variables as Bell's Inequality is violated and the coincidence rate (for initially unpolarized radiation) is observed to follow the well known Malus law
As the Bell test experiments can in this way be explained on a classical basis, they do therefore not introduce any new aspects into physics and in particular do not invalidate the objective physical reality of the polarization of radiation (and consequently neither lead to the conclusion of the existence of a non-local entanglement).
www.physicsmyths.org.uk /bell.htm   (1492 words)

  
 The CH74 Bell test
The Bell test of choice seems currently to be the 1969 Clauser-Horne-Shimony-Holt (CHSH) “two-channel” test, but this is (in its usual interpretation) valid for imperfect detectors only if the sample of detected coincidences (combining ++, +–, –+ and –– counts) is a fair one.
Bell himself had originally thought not of optical tests but of experiments using ions, which were to fly apart with opposite “spins” and each be detected as either “up” or “down”.
  In actual experiments the values of a, a¢, b and b¢ are chosen to be the “Bell test angles”, maximizing the predicted QM violation of (1).
freespace.virgin.net /ch.thompson1/Papers/CH74/CH74assumptions.htm   (2927 words)

  
 Experimental violation of a Bell's inequality with efficient detection : Nature   (Site not responding. Last check: 2007-10-22)
Early experiments to test Bell's inequalities were subject to two primary, although seemingly implausible, loopholes.
Clauser, J. and Shimony, A. Bell's theorem: experimental tests and implications.
Lamehi-Rachti, M. and Mittig, W. Quantum mechanics and hidden variables: a test of Bell's inequality by the measurement of the spin correlation in low-energy proton-proton scattering.
www.nature.com /nature/journal/v409/n6822/full/409791a0.html   (2992 words)

  
 Mesons violate Bell’s inequality (November 2003) - News - PhysicsWeb
Experiments to test Bell’s inequality involve measuring the properties of pairs of particles that are space-like separated in the sense of special relativity: in other words, there is no time for a light signal to travel between them within the duration of the experiment.
In a typical Bell’s inequality experiment the polarizations of a pair of photons are measured as the relative angle between the axes of polarizers making the measurements is varied.
Bell and others showed that it was possible to distinguish between quantum mechanics and these hidden-variable theories in a certain type of experiment that measure a parameter known as S. Put simply, the local theories predict that S will always be less than two, whereas the quantum prediction is S = 2√2.
www.physicsweb.org /article/news/7/11/3   (452 words)

  
 The EPR Paradox and Bell's Inequality Principle
In 1964 John Bell proposed a mechanism to test for the existence of these hidden variables, and he developed his inequality principle as the basis for such a test.
A series of experiments was conducted by Aspect ending with one in which polarizer angles were changed while the photons were `in flight'.
Experimental tests of Bell's Inequality are ongoing but none has yet fully addressed the issue raised by Franson.
math.ucr.edu /home/baez/physics/Quantum/bells_inequality.html   (2076 words)

  
 Labs21 2005 Conference Abstracts: A1
A test agent (tracer gas; usually sulfur-hexafluoride, SF6) is introduced inside the hood and the amount of "contaminant" that escapes the hood's sash opening, or face, is measured.
This test is not performed using a human operator conducting experiments inside the hood.
Bell is a Certified State Energy Auditor in New Mexico and a Registered Professional Engineer in both New Mexico and California.
www.epa.gov /lab21gov/conf/past/2005/abstracts/a1_bell.htm   (587 words)

  
 Alexander Graham Bell | Inventor
On March 7, 1876, the U.S. Patent Office granted Bell a patent for a communication device for "transmitting vocal or other sounds telegraphically." However, in 2002, the United States House of Representatives passed a bill conferring recognition for the invention of the telephone to Antonio Meucci.
Bell reasoned that it would be possible to pick up and transmit the sound of the human voice using an adaptation of his "harmonic telegraph." In 1875, along with his assistant Thomas A. Watson, Bell constructed instruments that transmitted recognizable voice-like sounds.
In 1876, three days after he received his first patent, Bell and Watson, located in different rooms, were about to test the new transmitter described in the patent.
www.lucidcafe.com /library/96mar/bell.html   (651 words)

  
 DrChinese Presents Bell's Theorem   (Site not responding. Last check: 2007-10-22)
Bell was aware that there were some unusual cases in which pairs of particles could be created that had an unusual property - they remained connected in some way even after they were separated.
Tests of Bell's Inequality are commonly called tests of the EPR Paradox, or simply Bell tests.
The experiments of Alain Aspect et al, especially the 1981 tests using time-varying analyzers, have shown that Bell's Inequality IS violated and the predictions of QM have been supported.
www.drchinese.com /Bells_Theorem.htm   (2683 words)

  
 Bell's Inequalities -- from Eric Weisstein's World of Physics
An infinite class of inequalities formulated by Bell (1964) which seemed to be a physically reasonable condition of locality imposing restrictions on the maximum correlations of the measurements of a pair of spin 1/2 particles formed in the singlet state and moving freely in opposite directions, as considered in the Einstein-Podolsky-Rosen paradox.
Bell's inequalities can be tested in a laboratory experiment (under certain assumptions) because the statistical predictions of quantum mechanics are incompatible with any local hidden variables theory apparently satisfying only the natural assumptions of "locality," as shown by the predictions of Bell's inequality.
Bell, J. "On the Einstein-Podolsky-Rosen Paradox." Physics 1, 195-200, 1964.
scienceworld.wolfram.com /physics/BellsInequalities.html   (224 words)

  
 Introduction to EPR
The best proof I know for the test actually used in two out of Alain Aspect's three experiments is included as an appendix to my paper on the subtraction of accidentals, quant-ph/9903066.
In real experiments, it is necessary to allow for the fact that the detectors do not register every "particle", and to make any test possible auxiliary assumptions are needed (for a fairly comprehensive list, see Appendix A in my Tangled Methods paper, as well as quant-ph/9903066).
The tests had to be modified because in all real experiments it is known that detectors have low "efficiencies".
freespace.virgin.net /ch.thompson1/intro.htm   (656 words)

  
 Human Intelligence: The Bell Curve
The Bell Curve, in its introduction, begins with a brief description of the history of intelligence theory and recent developments in intelligence thought and testing, through the eyes of the authors.
In addition, the authors argue that IQ tests could be the most important indicator of potential employee success, and therefore should be allowable as an input to the hiring process.
The primary desideratum in all experiments is reduction of confusing variables: we bring all the buzzing and blooming confusion of the external world into our laboratories and, holding all else constant in our artificial simplicity, try to vary just one potential factor at a time.
www.indiana.edu /~intell/bellcurve.shtml   (5488 words)

  
 RetroPsychoKinesis Experiments Online
A variety of feedback programs translate the stream of random bits from the generator into various graphical representations which allow you to see the extent to which the bit stream is departing from the most probable result of an equal number of ones and zeroes.
The bell curve feedback program provides direct feedback of the extent to which the random bit stream diverges from the most probable expectation of an equal number of zeroes and ones.
Your goal is to attempt to influence the pointer to move to the right or left, toward the low-probability "tail" of the curve.
www.fourmilab.ch /rpkp/experiments   (651 words)

  
 TCIY - 1 The Computing-Element Reality Model
Various physics experiments, such as the double-slit experiments done with electrons and also neutrons, contradict the old idea that a particle is self-existing independent of everything else.
For the particles studied by physics, these experiments show that the existence of a particle, knowable only thru observation, is at least partly dependent on the structure of the observing system.
Given the distance between the particles and the extent to which the synchronous state changes are measured as being simultaneous, it appears necessary that an instantaneous much-faster-than-lightspeed communication is involved in coordinating these synchronous state changes for the widely separated particles.
www.johmann.net /book/ciy1-1.html   (920 words)

  
 Myswizard » Quantum entanglement   (Site not responding. Last check: 2007-10-22)
The correlations predicted by quantum mechanics, and observed in experiment, naively appear to be inconsistent with the seemingly obvious principle of local realism, which is that information about the state of a system should only be mediated by interactions in its immediate surroundings.
However, in 1964 Bell derived an upper limit, known as Bell’s inequality, on the strength of correlations for any theory obeying “local realism” (see principle of locality).
High efficiency and high visibility experiments are now in progress which should accept or reject those loopholes.
www.myswizard.com /2006/03/22/quantum-entanglement   (596 words)

  
 Bell_John (print-only)
Reinhold Bertlmann, who himself did important work with Bell, has written a book titled Anomalies in Quantum Field Theory [10], and the two surviving members of ABJ, Adler and Jackiw shared the 1988 Dirac Medal of the International Centre for Theoretical Physics in Trieste for their work.
Bell himself became a Fellow of the Royal Society as early as 1972, but it was much later before he obtained the awards he deserved.
In the last few years of his life he was awarded the Hughes Medal of the Royal Society, the Dirac Medal of the Institute of Physics, and the Heineman Prize of the American Physical Society.
www-groups.dcs.st-and.ac.uk /~history/Printonly/Bell_John.html   (2946 words)

  
 Physics Colloquium Series » Special seminar: From Einstein intuition to quantum bits: The amazing properties of ...
In the early 1980s, with collaborators in France, he performed the crucial “Bell test experiments” that showed that ‘ghostly action at a distance’ does in fact occur when two entangled particles are separated, in a manner that can only be explained by quantum mechanics.
He was also a pioneer in development of laser cooling of neutral atoms and is currently leading experiments in Bose-Einstein condensates that are at the cutting edge of the field.
A test of EPR correlations in B0-B0 bar pairs at the Belle experiment
www.physics.uq.edu.au /colloquium/?p=35   (339 words)

  
 MIND Exchange
We have been told that experiments agree with all the predictions of quantum theory, including those that involve the impossible - the Bell test experiments, that are supposed to show totally incomprehensible effects of separated particles on each other.
The bell tests have their own known loopholes, and can entirely be explained by local realist models.
In testing this model I have implemented a series of experiments using spontaneous gamma-rays from either 109Cd or 57Co, whereby a primary gamma-ray is split and detected in coincidence in two detectors.
www.kurzweilai.net /mindx/show_thread.php?rootID=50041   (4012 words)

  
 experiments - OneLook Dictionary Search
Experiments : Discovering Nutrition: Interactive Glossary [home, info]
Example: "We are experimenting with the new drug in order to fight this disease"
Phrases that include experiments: factorial experiments, pressure experiments, asch conformity experiments, bell test experiments, common experiments, more...
www.onelook.com /?w=experiments   (173 words)

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