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  • Title: The Center for Quantum Philosophy
    Descriptive info: .. The Center for Quantum Philosophy.. Discovering invisible causes behind the visible world.. B.. ell experiments demonstrate (within the limits of a few rather eccentric loopholes).. nonlocal.. correlations between space-like separated events, which cannot be explained by means of relativistic influences bounded by the velocity of light.. This means that one has to give up the view that the outcomes at each part of the setup result from properties preexisting in the particles before measurement: outcomes in Alice's (respectively Bob's) lab cannot be explained by the properties the photon carries when leaving the source and the settings of Alice's (respectively Bob's) measuring devices.. T.. he.. before-before or Suarez-Scarani experiment.. demonstrates that these.. correlations cannot be explained in terms of "before" and "after", by time-ordered nonlocal influences.. Giving up the concept of locality is not sufficient to be consistent with quantum experiments, one has to give up nonlocal determinism, i.. e.. the view that one event occurring before in time can be considered the cause, and the other occurring later in time the effect.. The time-notion makes sense only in the domain of the relativistic local phenomena.. The nonlocal correlations cannot be explained by any history in spacetime,.. they come  ...   even stronger confirmation of this result is expected from new experiments in progress according to the Colbeck-Renner proposal.. P.. utting together the results of these three experiment types one can conclude that in entanglement experiments local random events experience influences from outside spacetime to produce nonlocal order.. Quantum correlations unite in the same phenomena full local randomness and nonlocal timeless order.. Center for Quantum Philosophy.. , based in Zurich and Geneva, aims at wide spreading this discovery, and to stimulate the discussion about its cultural and philosophical implications.. I.. n this web site, you will find:.. A talk by.. John Bell.. explaining his theorem at the CERN (Geneva), followed by an exciting discussion on scientific and philosophical issues.. Tutorial-presentations.. explaining the basic principles of the quantum world, and the relevance of the before-before experiment.. A list of.. publications.. presenting the experiment and discussing his scientific, metaphysical and cultural implications.. An.. biographical note.. telling the story behind the mentioned experiment.. Correspondence.. with interested readers.. Top of page.. Home.. |.. John Bell.. Presentations.. History.. Publications.. Links.. Contact us.. For any query or feedback on this site, feel free to send mail to the.. Webmaster.. Last updated on 29 october 2007 21:24:24 +0100..

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  • Title: John Bell
    Descriptive info: Video and Transcription.. Video of John Bell.. explaining his theorem.. at the CERN in Geneva, the 22nd January 1990.. Read the.. transcription.. of the talk and part of the discussion.. See also the pages:.. http://www.. youtube.. com/watch?v=V8CCfOD1iu8.. informationphilosopher.. com/solutions/scientists/bell/inequality_video/.. Last update on 16 nov.. 2007 17:57:23 +0100..

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  • Title: Presentations
    Descriptive info: Presentations.. Is Science Compatible with Our Desire for Freedom?.. Experts Meeting organized by the Center for Quantum Philosophy.. and the Social Trends Institute at IESE Campus-Nord.. Barcelona, Spain | October 28-30, 2010.. All the talks and discussions in YouTube.. Is there Time in the Quantum World?.. The basic principles of the quantum world,.. Copenhagen interpretation, EPR-Bohm Argument,.. Bell's Theorem, Before-Before experiment.. Appendix 1.. Quantum Mathematics.. Only german version available.. Appendix 2.. Applying Quantum Mathematics to 2-particles Experiments.. Animation: A Quantum Interferometer.. This animation may help understanding quantum interference experiments.. Last update on 8 jan 2008 08:36:23 +0100..

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  • Title: History
    Descriptive info: The Story behind the Experiments.. During 1988, I came in contact with.. in the.. CERN.. , the.. European Laboratory for Particle Physics.. in Geneva.. With his support and collaboration, I launched the activity of the.. , promoting talks in the CERN and in various European universities.. These activities aimed to stimulate the discussion on the philosophical and scientific challenges raised by the quantum theory, and show that this theory is now an integral part of knowledge and culture.. In the CERN held talks among others: Herwig Schopper, John Bell, Constantin Piron, Nicolas Gisin, Asher Peres, John Ellis.. Particular mention deserves a colloquium in Cologne (Germany) on May 13-14, 1990, organized in collaboration with the Lindenthal-Institute and the Institute for Theoretical Physics of the University of Cologne, at which participated two major exponents of Nonlocality research: John Bell and Anton Zeilinger (see.. [1].. in German).. During a colloquium organized in the CERN on January 22, 1990, John Bell has been asked whether he thought that relativity and quantum mechanics could be incompatible.. John Bell answered:.. No, I can't say that, because I think someone will find one day a way to demonstrate that they are compatible.. But I haven't seen it yet.. To me, it's very hard to put them together, but I think somebody will put them together, and we'll just see that my imagination was too limited.. (see.. [2].. ).. This answer encouraged me to investigate in depth the tension between quantum mechanics and relativity.. Quantum mechanics predicts correlated outcomes in space-like separated regions for.. experiments using two-particle entangled states.. Bell-type experiments, conducted over the past two decades, suggest a violation of local causality: Statistical correlations are found in space-like separated detections: two photons, far away from each other and obliged to choose between two values (say between + or —), choose the same value, and we get either the joint outcome [+,+], or [—,—].. Violation of Bell’s inequalities.. ensures that these correlations are not predetermined by local hidden variables.. Entangled particles behave as if there was a.. faster than light connection.. between them (see.. experiments.. Multisimultaneity.. I was strongly convinced that it should be possible to give a time-ordered causal explanation of nonlocal correlations, in terms of before and after.. Indeed, such a description is very well possible in conventional Bell experiments, in which all apparatuses are standing still in a laboratory frame.. Since the emission time of the photons is not exactly the same, and the fibers guiding the photons from the source to the measuring devices don’t have exactly the same length, according to the clock defined by the laboratory’s inertial frame, one of the measurements always takes place before the other, and the particle arriving later can be considered to take account of the outcome of the one arriving before.. In fact, this is the way Bell tried to explain things, and, in doing so, he came to discover quantum nonlocality (see.. and.. Orderings with one measurement before and the other after in time are referred to as.. before-after.. or.. after-before.. timings.. In experiments with all measuring devices at rest, it is possible to explain quantum correlations through time-ordered causality.. But what about experiments with moving apparatuses in which several relevant frames are involved? In this case, different clocks watch the arrival times, and what is “after” according to the laboratory clock may become “before” according to one moving clock.. Then, it is possible to define other time orderings: If each measuring device in its own reference frame is the first to select the output of photons, we have.. before-before timing.. If each measuring device in its own reference frame selects the photon output after the other, we have.. after-after timing.. Is it also possible to give a time-ordered causal explanation for relativistic experiments using apparatuses in motion? I assumed it was, and developed an alternative nonlocal description termed “.. multisimultaneity.. ”, in which the time-ordered description of the nonlocal correlations extends to experiments with before-before and after-after timings.. Consider, for instance, experiments in which the measuring devices are in motion in such a way that each of them, in its own reference frame, is the first to select the output of photons (before-before timing).. Then each particle’s choice will become independent of the other’s and, according to multisimultaneity, the nonlocal correlations should disappear.. In contrast, quantum mechanics requires that the particles stay non local, correlated independent of any timing, even in such a before-before situation.. As a matter of fact, the available conventional experiments at that date did not allow to decide between multisimultaneity and quantum mechanics.. A new experiment using apparatuses in motion was needed.. Monique et Marcel Odier.. Since it appeared rather difficult to obtain public funding for such an experiment, in 1992 I did a fund rising and was introduced to.. Marcel  ...   measuring devices should be set in motion in a real experiment.. Since each outcome implies a choice between two values (.. +.. —.. ), one must set in motion the device that is supposed to be that in which the choice of the outcome value takes place (choice-device).. This means that if one invokes a description assuming quantum collapse at detection, one has to put the detectors in motion; if one invokes a description without quantum collapse (in the line of Bohm’s theory), the monitored beam splitters.. Since to put beam-splitters in motion involved great technical difficulties,.. decided to begin by putting detectors in motion.. On November 26-27, 1998 we organized in Geneva a colloquium with.. Ian Percival, Sandu Popescu.. , and.. to evaluate the work in progress.. All of them agreed that the experiment with moving apparatuses was crucial to investigate the tension between Relativity and Quantum Mechanics.. In February 2000 we got the first results of the experiment using one detector in motion.. They were in agreement with quantum mechanics (see.. Hugo Zbinden - André Stefanov.. Meanwhile.. had an excellent idea: to take advantage of the fact that traveling acoustic waves can act as moving beam splitters, and use them to realize “before-before” experiments.. After a technological feat,.. did them in June 2001.. On Friday, the 22nd of June 2001 in the morning, I was in Geneva for the Colloquium where.. presented the first results he was obtaining.. These refuted multisimultaneity, and I got the impression I was assisting to my burial.. After lunch.. André.. and myself went to the laboratory to control the setup, and we found that, because of an error in the orientation of the measuring devices, the experiments had been done with “before-after” instead of before-before timing.. So, in the annual meeting of the Foundation Odier in the evening of that Friday, no conclusive results could be presented, and the hope to beat quantum mechanics remain fully alive.. On Monday the 25th,.. restarted the measurements with the correct configuration.. On Tuesday the 26th at 19:15, I suddenly became aware that my confidence in beating quantum mechanics was the product of a prejudice: I was assuming that causality always sticks to time.. But nothing speaks against the idea of phenomena being produced by causes that are not bound to the limits of space and time.. I then understood that this is the kind of causality behind the formalism of quantum mechanics.. Next morning I called.. , and communicate him my new expectation, that the correct measurements would confirm quantum mechanics, as it actually happened.. The final results.. The final results of the experiments with moving measuring devices (see.. ) rule out the possibility to describe the quantum correlations by means of real clocks, in terms of before and after ; nonlocal quantum phenomena cannot be described with the notions of space and time.. This means that.. there is no time ordering behind nonlocal correlations.. , so the causal order cannot be reduced to the temporal one.. Quantum correlations somehow reveal dependence between the events, or logical order.. Experiment shows that this dependence, or logical order, is beyond any real time ordering.. In the realm of the nonlocal quantum phenomena, things come to pass but the time doesn't seem to pass here.. This wonderful adventure had not been possible without the courage of.. for undertaking non-mainstream research, the experimental capabilities of.. and the generosity of.. Monique.. Antoine Suarez.. 2 April 2003.. Zurich.. About the author.. Dr.. took his Ph.. D.. in natural science at the.. Swiss Federal Institute of Technology.. Eidgenössische Technische Hochschule Zürich.. or ETH) in 1975.. While at ETH, he not only became interested in the philosophical significance of quantum mechanics but also in genetic epistemology.. For more than a decade, he was engaged in research on cognitive growth that led to the development of improved methods for teaching mathematics and science to children.. He directed the Swiss think tank,.. Institute for Interdisciplinary Studies.. (IIS), from 1985 to 1993, and, with major support from the.. Leman Foundation.. , he undertook studies that brought the insights of philosophers, theologians, and ethicists to bear on advances in science.. Antoine Suarez was the first (with Valerio Scarani in 1997) in proposing experiments using moving measuring devices to investigate the tension between quantum mechanics and relativity, especially whether there is a real-time ordering behind nonlocal influences.. He actively collaborated with Nicolas Gisin’s group in the realization of these experiments.. In addition to articles in scientific journals, chapters in volumes of collected works, and an early study on the relation of thought to action in adolescents, Dr Antoine Suarez is the co-editor, with.. Alfred Driessen.. , of the book.. Mathematical Undecidability, Quantum Nonlocality and the Question of the Existence of God.. (Kluwer, 1997).. Last updated on 16 nov 2007 18:00:24 +0100..

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  • Title: Publications
    Descriptive info: Nature establishes order without time.. In this page, you will find a section of scientific publications presenting the.. and the results, and a section of.. comments.. discussing the philosophical and cultural implications of the experiments.. Some of these documents are available on line.. You can read with Acrobat Reader the full text, when available, by clicking on any.. icon below.. (free).. Experiments.. 2008: Quantum randomness can be controlled by free will -a consequence of the before-before experiment.. arXiv: 0804.. 0871v1 [quant-ph].. The before-before experiment demonstrates that quantum randomness can be controlled by influences from outside spacetime, and therefore by immaterial free will.. Rather than looking at quantum physics as the model for explaining free will, one should look at free will as a primitive principle for explaining why the laws of Nature are quantum.. 2008: Nonlocal "Realistic" Leggett Models Can be Considered Refuted by the Before-Before Experiment.. Found Phys (2008) 38: 583-589 DOI 10.. 1007/s10701-008-9228-y.. Nonlocal "realistic" Leggett models can be considered refuted by the before-before experiment.. "Single preferred frame" models are not refuted by this experiment but bear severe oddities.. 2007: Classical Demons and Quantum Angels: On 't Hooft's deterministic Quantum Mechanics.. arXiv:0705.. 3974v1 [quant-ph].. The article discusses the free will assumption in quantum mechanics, and proposes the quantum homeostasis hypothesis for explaining consciousness and sleep.. It is argued that 't Hooft's deterministic program does not disenchant the quantum world but rather inspires the incantation of the classical one.. 2003: Entanglement and Time.. quant-ph/0311004.. Article about the implications of the experiments with moving measuring devices.. It is argued that recent experiments testing Multisimultaneity prove that quantum entanglement occurs without the flow of time.. Bohm's theory cannot be considered a real temporal description.. 2003: Quantum entanglement with acousto-optic modulators: Two-photon beats and Bell experiments with moving beam splitters.. André Stefanov, Hugo Zbinden, Nicolas Gisin and Antoine Suarez.. Physical Review.. A, volume 67, 042115.. Full-length article about the experiment using acoustic waves as moving beam-splitters.. We present an experiment testing quantum correlations with frequency shifted photons.. We test Bell inequality with two-photon interferometry where we replace the beam splitters with acousto-optic modulators, which are equivalent to moving beam splitters.. We measure the two-photon beats induced by the frequency shifts, and we propose a cryptographic scheme in relation.. Finally, setting the experiment in a relativistic configuration, we demonstrate that the quantum correlations are not only independent of the distance but also of the time ordering between the two single-photon measurements.. 2002: Quantum Correlations With Moving Observers.. N.. Gisin, V.. Scarani, A.. Stefanov, A.. Suarez, W.. Tittel and H.. Zbinden.. Optics Photonics News.. , December 2002, 51.. Short presentation of the experiments with moving devices.. The experiments with moving measuring devices can be considered a fundamental test of quantum mechanics and information.. The December issue of Optics and Photonics News highlighted some of the most exciting research to emerge in during 2002.. The GAP-Optics experiments studying the quantum correlations with moving observers was a first for a new kind of experiment to test quantum non-locality.. 2002.. :.. Quantum Correlations with Spacelike Separated Beam Splitters in Motion: Experimental Test of Multisimultaneity.. André Stefanov, Hugo Zbinden, and Nicolas Gisin - Antoine Suarez.. Physical Review Letters.. volume 88, number 12.. Article about the experiment using acoustic waves as moving beam-splitters.. Multisimultaneity is a causal model of relativistic quantum physics which assigns a real time ordering to any set of events, much in the spirit of the pilot-wave picture.. Contrary to standard quantum mechanics, it predicts a disappearance of the correlations in a Bell-type experiment when both analyzers are in relative motion such that each one, in its own inertial reference frame, is first to select the output of the photons.. We tested this prediction using acousto-optic modulators as moving beam splitters and interferometers separated by 55 m.. We did not observe any disappearance of the correlations, in agreement with quantum mechanics.. 2001.. Is there  ...   proposed relativistic nonlocal description (Multisimultaneity) is applied to a so-called “after-after” experiment with 2 non-before impacts, leading to new rules of calculating the joint probabilities, and to predictions conflicting with quantum theory.. Does entanglement depend on the timing of the impacts at the beam-splitters?.. A.. Suarez and V.. Scarani.. Lett.. A, 232, 9-14 390 (.. quant-ph/9704038.. First article to propose experiments using measuring devices in motion and the relativistic “before-before” timing.. A new nonlocality experiment with moving beam-splitters is proposed.. The experiment is analyzed according to conventional quantum mechanics, and to an alternative nonlocal description (Multisimultaneity) in which superposition depends not only on indistinguishability but also on the timing of the impacts at the beam-splitters.. Comments.. 2007: Free will - is our understanding wrong?.. Zeeya Merali.. New Scientist No.. 2615, 04 August 2007.. Magazine-article presenting the before-before experiment with beam-splitters in motion, and commenting that Quantum Mechanics beats both, time and ‘t Hooft’s deterministic view.. Corrections to the experiment’s description in the New Scientist’s article.. 2003: Le temps est différent des propriétés qu'on lui attribue.. Etienne Klein interviewed.. Science et Vie, January 2003.. Etienne Klein comments the results of the Geneva experience testing Multisimultaneity and concludes that the quantum correlation is caused without any flow of time but, once produced, it becomes engraved in time.. 2003: Le temps n'existe pas !.. Hervé Poirier.. Magazine article on the experiments with moving apparatuses stressing that in the realm of the nonlocal quantum phenomena things come to pass but the time doesn't seem to pass here.. The article points out also the relevance of quantum entanglement for practical applications as cryptography.. 2002: Quantum correlations with spacelike beamsplitters in motion.. Contribution presenting the experiment with moving beam-splitters to the Young Researchers Competition in Honor of John Archibald Wheeler, organized by the Templeton Foundation in Princeton, March 15-18, 2002.. 2001: Spooky twins survive Einsteinian torture.. Ch.. Seife.. Science.. , Vol.. 294, 9 November 2001.. Magazine-article commenting the results of the experiments with moving beam-splitters and highlighting the conclusion that the notion of time does not make sense in the quantum world, quantum entanglement cannot be described in terms of before and after.. sciencemag.. org.. 2001: Corrélations quantiques insensibles à l'espace et au temps.. Nicolas Gisin, André Stefanov, Antoine Suarez, Hugo Zbinden.. Communiqué de presse du.. 31.. 10.. 2001.. sur l'expérience avec appareils en mouvement.. Full text in French:.. communique_de_presse.. doc.. (MS Word).. 2001: Quantum Correlations insensitive to space and time.. Press-communiqué dated.. about the experiment with moving measuring devices.. Full text in English:.. press_communique.. 2000: 'Spooky Action' Passes a Relativistic Test.. 287, 17 March 2000.. Magazine-article commenting the results of the experiments with moving detectors and stressing the relevance of testing Quantum Mechanics against Multisimultaneity in experiments using measuring devices in motion.. 1997:.. Driessen and A.. Suarez, Editors.. , Kluwer Academic Publishers, Dordrecht, The Netherlands.. This book offers a series of contributions written by scientists interested in a philosophical reflection on recent advances of science.. The reader will find generally understandable presentations of recent results from mathematics, like the theorems of Gödel and Turing, and physics, mostly related to EPR Gedanken experiments and Bell's theorem.. In the case of physics, special attention is directed to old and new experiments supporting a nonlocal approach.. Especially worth mentioning is the until now unedited contribution of the late John Bell on Bell's theorem held on 22 January 1990 in a Seminar at CERN.. Profound scientific theorems in modern mathematics and physics shed new light on two fundamental questions often only implicitly dealt with: is mathematical truth a purely man-made construction and is the physical reality behind the phenomena at least in principle always observable? The answers to both questions are closely related to the possible existence of an omniscient and omnipotent being.. In this sense mathematical undecidability and quantum nonlocality are proposed as a possible road to metaphysical principles and eventually to God.. 2007 18:02:23 +0100..

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  • Title: Correspondence
    Descriptive info: If you wish.. to put a letter in our Correspondence section (this one),.. to signal us a relevant.. Publication.. Link.. to be added in our lists,.. to ask some questions about the.. and their implications,.. please.. send us an e-mail.. Jump to.. cor 030301.. cor 030302.. cor 030303.. cor 030304.. cor040101.. cor/040101.. January 1, 2004.. Regarding the article about your experiment in PM-Magazin (Germany), November 2003, I would like to put the following 3 questions:.. 1st question:.. Why does a photon once passe a half-silvered mirror and once not? If one could explain this behavior exactly, then maybe one could also explain the identical behavior of two different photons.. 2nd question:.. How are you producing the photons, which behave the same way at the mirrors? Do you separate them by another (half-silvered) mirror? If yes, it sounds logical, that they behave the same way.. If they are produced consecutively by a (one) laser, it is not less logical for me that they will behave the same way.. Or maybe the universe is pulsing, so that all half-silvered mirrors in the universe will pass the photons for a while and later not, so that the behavior will be clear - even if there is a small time lack between the arrivals of both photons.. If they are building a relationship by accident, how do the photon, which will pass the mirror, know, that there is another photon, which will pass another (or the same) mirror in a few ticks? Will it call Is there another photon anywhere in the universe which will pass a mirror? Please behave the same way - I think not.. Why else should they communicate with each other? I do more believe, that the production of the photons is the key to the same behavior, not the way, the target or something else.. 3rd question:.. Regarding the experiment with the moving mirror.. I don’t see, why one cannot determine, which photon impacts the mirror first.. It’s right, that the time in fast moving object runs slower.. But due to the fact, that both photons have the same speed, that is to say the speed of the light, the time for both photons elapses the same way.. It doesn’t matter, how fast the mirrors are moving - relatively to each other.. So the result must be, that the photon, which directs to the away moving mirror will impact it later.. HOW it looks like for the observer is not relevant, because this is relatively and not absolutely.. Richard Knobloch.. cor/040101a.. January 13, 2004.. 1st question:.. f one considers only the outcomes occurring at one side of the setup in our experiment, these outcomes look completely random: 50% of the times the photon passes the beam-splitter (i.. the half-silvered mirror), ad 50% not.. It is impossible.. in principle.. to know how a single photon will “exactly” behave.. One can assume that an individual quantum event is very much like a choice: In fact, in our experiment the measuring devices are adequately referred to as “choice-devices”, because at these devices a choice between two possible values takes place.. Suppose you are driving a car: you cannot know whether the car before you will turn to the left or to the right at the next crossing, because you cannot read the mind of the driver.. I think that the individual quantum event can be considered an “individual act of creation” (as Anton Zeilinger says), just in the same sense as the driver’s choice between left and right is one: the decision “creates” a bit of information (obviously, in neither case there is creation of energy).. Then, an important conclusion of quantum experiments like ours is that the very idea of quantum randomness is connected with the idea of order and intention.. Indeed, if one considers only the outcomes occurring at one side of the setup these outcomes look completely random.. But if one compares the outcomes at one side with those at the other side, one discovers that there is intention, ordering, and dependence.. Hence, intention and randomness are not incompatible at all, and can originate from the same cause.. It is true, however, that today we don’t know yet which are the rules allowing us to connect quantum randomness and intelligent actions on the level of the brain.. But the very existence of nonlocality clearly suggests that such a connection is possible in principle, and to find how it works in our brain is surely one of the great scientific challenges for the coming years.. In our experience, a laser beam illuminates a so-called nonlinear crystal, in which each photon of the laser converts down to a pair of photons.. One photon of this pair is guided to a measuring device at the right side of the setup, and the other photon is guided to a measuring device at the left side.. Both measuring devices (and the corresponding beam-splitters) are 55 m separated from each other.. Each of them has a switch the physicist can arbitrarily set in different positions (.. a, b, c,….. ) to regulate the functioning of the device.. One can arrange the things so that if both switches (the left side switch and the right side one) are set on the same position, one has the situation in which both photons behave exactly the same way and, therefore, the outcomes are only.. concordances.. (i.. both photons pass or both doesn’t pass).. The explanation you propose in your question is the same Einstein proposed: The photons behave like twins that carry a same genetic program and show the same behavior when they meet the same environmental conditions.. Suppose now a physicist on the left side switches on position.. a.. , and a physicist on the right side on.. b.. Then one gets also some.. discordances.. (one photon pass and the other doesn’t pass).. The physicist John Bell proved in 1965 that if Einstein’s hypothesis is true then the statistic of the outcomes should fulfill a mathematical relation now called Bell’s inequality: The probability to get a discordance with the switches in positions (.. a, c.. plus.. probability to get a discordance with the switches in positions (.. b, a.. cannot be less.. than the probability to get a discordance with the switches in positions (.. b, c.. A number of experiments performed in the last 20 years show that nature violates this inequality.. This violation proves that the production of the photons is NOT the key to the same behavior.. We have to admit some kind of direct link between the two particles and, therefore, Einstein’s hypothesis is wrong.. By the way, one can also arrange experiments using photons that come from different sources.. You mention very appropriately another possibility to escape this conclusion: the universe could be pulsing, so that all half-silvered mirrors in the universe are already connected even before the photons leave the source.. But this possibility has also been excluded in the experiments: in fact, the setting of each switch occurs when the photons are already in flight, immediately before they arrive to the measuring devices, so that only links faster than light could ensure a connection between the beam-splitters.. One can attribute a time frame only to objects with rest mass.. Photons have no rest mass and have no clock.. Therefore it does not make sense to say: “the time for both photons elapses the same way”.. To establish a time ordering you must take a clock, but to define a clock you have to use the state of movement of some massive object.. Since in our experiment the choices are supposed to occur at the half-silvered mirrors, we determine the chronology of the events by means of the clocks associate to such mirrors.. Through adequate distances and velocities we arrange the “.. before-before.. ” situation, in which according to the clock of the half-silvered mirror at the left side the measurement at this mirror takes place.. before.. the measurement at the right side, and according to the clock of the half-silvered mirror at the right side the measurement at this mirror takes place before the measurement at the left side.. Since even in the “.. ” situation the correlations don’t disappear, we have to admit, as you suggest, that someone is calling: “Is there another photon anywhere in the universe which will pass a mirror?”, and if it is, he creates a dependence between the two “passing events” that astonishingly doesn’t correspond to any time ordering.. Top of message.. cor/030304.. March 17, 2003.. I read an article in the French magazine "Science et Vie" about your experiment with entangled photons.. It was very interesting.. I'm not a professional physicist; I'm a computer professional.. What I thought when reading the article is very simple: it made me think on coupling.. Imagine 2 parallel electrical circuits A and B with switches to light either a green bulb, or a red bulb.. This means that A can have 2 colors Green or Red, and B also can have 2 colors Green and Red.. If both switches are coupled together, A and B will be Green at the same time, or Red at the same time.. Now, in the computer business, we are used to think in layers.. For instance, for networks, there is the ISO model with 8 layers.. The lowest level is hardware, and the highest is application.. This can be the same in physics.. The hardware level can be  ...   Beauregard/Cramer's hypotheses) you refer to, it seems to me that it leads to a big problem in situations in which the two measurements lie time-like separated, as it is the case in the situation you describe (“the first photon being measured after only 1 meter path, and the second one in another galaxy”).. In this case “backwards causation” means that the measurement of photon 2 determines the outcome of photon 1.. But this would imply that at the time T, at which photon 1 is measured the outcome of this event 1 is determined by another event 2 (the measurement of photon 2), to which at time T one cannot attribute any existence at all in any possible inertial frame (of the source or other), for the event 2 lies in the future light cone of the event 1.. I think that this does not make sense.. Actually, “backwards causation” is the strongest form of the bias that causality is always bond to the flow of time (you could also say the bias that all causal links have to be essentially Lorentz invariant): If you cannot bind causality to the time flowing forwards, you bind it to the time flowing backwards! As far as such a view does not imply observable consequences there is no problem in maintaining it.. Nevertheless according to Olivier Costa de Beauregard backwards causation should have observable implications in experiments involving subjects who enjoy psi-capacities.. In experiments with entangled particles, such psi-subjects are supposed to be capable of influencing on purpose the probability to get a particular outcome, say +, on one side of the setup, and because entanglement they would also change faster than light the corresponding probability on the other side.. This would imply the possibility of signaling faster than light and, therefore, of changing the past.. As I have been told such experiments are in preparation, so let us await the results.. cor/030302.. February 09, 2003.. Here is a question about the relation between decoherence and non-locality.. It is now generally acknowledged, after Haroche's and Raimond's experiments, that the quantum measurement problem (wave-packet reduction) is well explained by the theory of decoherence.. However, decoherence is not an instantaneous process.. In the case of measurement of the polarization of a photon, like in Aspect's or Gisin's experiments, what happens to the second photon when the first one is measured? According to the theory of decoherence, the first photon interacts during a certain time (very short, but that does not matter) with its environment.. How is this interaction transmitted to the second photon, and how can this second photon transmit this information to its own environment?.. I discussed that with a couple of French physicists (for example Herve Zwirn) but there was no conclusion.. Jean-Pierre Pharabod.. (co-author, with Sven Ortoli, of Le Cantique des quantiques ).. February 10, 2003.. You have surely noticed that, in my previous mail, I keep the conventional interpretation of Aspect-like experiments, i.. that one of the photons is measured first , or, if one prefers, that there is a before and an after.. I think that the problem of the relation between decoherence and non-locality is better understood with this conventional interpretation.. This problem was already pointed out in the postscript to the last edition of Le Cantique des quantiques (La Decouverte, 1998): (in French, but I think that you speak French).. Le mystère de la mesure quantique est sans doute éclairci, mais cela ne fait que renforcer celui de la non-localité.. En effet, la décohérence, quand on en fait la théorie, n'est pas un phénomène instantané.. Et dans une expérience du type de celle d'Aspect, pour certaines orientations des détecteurs, c'est le premier photon détecté qui fixe la polarisation de l'autre, qui peut en être très éloigné.. Le processus de mesure qui, bien que très bref, dure un certain temps, a sa contre-partie ailleurs dans l'espace.. cor/030302a.. March 1, 2003.. You address the interesting question of the relationship between two main mysteries of quantum mechanics:.. measurement.. nonlocality.. I would like to begin with a comment on.. To a certain extent you can compare this state of things with the situation around the definition of death.. Death, doctors say, means the irreversible breakdown of the brainstem functions.. To establish death physicians have a checklist, the most important item of which is the lack of spontaneous movements, first of all spontaneous breathing.. Death, the irreversible breakdown of brainstem, does not certainly occur because a doctor establishes it, but nobody can tell when it does exactly occur.. Up to now nobody knows how much harm exactly defines the irreversible breakdown of brainstem.. In any case, the conviction that death is irreversible means that we accept our incapability of mastering, even in principle, certain natural processes.. Similarly quantum physicists admit that in measurement something happens that goes beyond our capability of restoring.. The conditions required in order that a measurement takes place are not yet clearly defined: we don’t know whether measurement is determined by a still unknown new constant of nature, or by some mathematical impossibility theorem.. I come now to.. Effectively, as you say, the conventional interpretation of Aspect-like experiments is that one of the photons is measured first , or, if one prefers, that there is a before and an after.. John Bell used this explanation, and doing so he came to discover the astonishing quantum-mechanical nonlocality.. This way of explaining things fits perfectly well for all experiments in which all apparatuses are standing still in the laboratory frame.. How is the interaction of the first photon with its environment transmitted to the second, you ask.. If you assume that measurement means choice, then no interaction is transmitted but only information: When the first photon is measured an outcome is selected at random, and when the second photon is measured the outcome is selected taking account of the choice done before for the first photon.. As you know the quantum mechanical formalism forbids us to use the link between the two measurements to phone faster than light.. This means that this link is an unobservable one.. I tried to extend the “conventional” view to experiments with apparatuses in motion, in which two different clocks watch the arrival of the photons.. The experiments prove that such an extension fails: the dependence the correlations reveal has no temporal counterpart.. We have obliged Quantum Mechanics to tell us what its formalism means.. In this sense the mystery of nonlocality has been clarified to some extent.. By contrast, it seems that we are still far away of understanding why and when the irreversible choice in a measurement process takes place.. cor/030301.. February 07, 2003.. In http://www.. cfqp.. org you write:.. ”Recent experiments have put in evidence that the correlations caused by a two-particles quantum entanglement cannot be described in terms of before and after : The time-notion makes sense only in the domain of the relativistic local phenomena.. ”.. This is certainly false, as proven by Bohmia ļme an s.. br>.. As far as I understand, you do not question the agreement between the predictions of BM and standard QM as well as the agreement of the predictions of QM with observation.. As well, in BM quantum entanglement is described in terms of before and after.. You may not like BM, many do.. But you don't like the description X certainly differs from cannot be described.. Ilja Schmelzer.. cor/030301a.. Many thanks for your comment.. First of all let me say that I like Bohmian Mechanics (BM), as John Bell also did.. In fact, Multisimultaneity is nothing other that applying consequently the spirit of Bohmian Mechanics to experiments with apparatuses in motion.. Bohm's theory has been the first attempt to cast nonlocality into a temporal scheme.. It uses a unique preferred frame or absolute time, in which one event is caused by some earlier event by means of instantaneous action at a distance.. As you state Bohmian Mechanics makes the same predictions, as Quantum Mechanics.. Nevertheless, if one tries to cast nonlocal causality into only one preferred frame, then it is not more reasonable to connect a cause event to an effect event in that frame rather than in some other frame.. Effectively a single preferred frame (.. quantum ether'') is experimentally indistinguishable , John Bell said: The predictions would remain the same even if one assumes that the preferred frame is a virtual entity changing from experiment to experiment.. For this reason one is tempted to think that Bohm introduces absolute time just because he wishes to justify a causal description, but in the end, an untraceable quantum ether'' is essentially the same as deciding arbitrarily which event depends on which one.. What is more, in the particular case, possible in principle, of both measurements taking place at exactly the same time in the preferred frame, the only way of establishing which event depends on which is by arbitrary decision.. Actually, Bohmian Mechanics (and Quantum Mechanics too) can be considered a causal description but not a real temporal one, and to date it has not lead to experiments capable of testing the timing-independence of quantum entanglement.. Taking account of your comment, I would like to precise the meaning of what I wrote as follows: Recent experiments with relativistic setups prove that quantum entanglement cannot be described in terms of “before” and “after” by any set of real clocks or experimentally distinguishable inertial frames.. Last update on 16 nov 2007 18:03:38 +0100..

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  • Title: Links
    Descriptive info: Relevant links in no particular order:.. Nicolas Gisin's Group for Applied Physics.. (GAP).. Anton Zeilinger's Group.. , University of Vienna.. Alfred Driessen's Home Page.. Humble Approach Initiative on Nonlocality.. Seminar.. The.. European Organisation for Nuclear Research.. : CERN.. Spanish Research Center on Science, Reason and Faith.. Quantum Philosophy Theories.. A.. John Steward Bell.. 's biography.. (28-jul-1928 / 1-oct-1990).. F.. ew other biographies.. (de Broglie, Einstein, Heisenberg, Schrödinger, Planck, etc).. Embryoperson : Showing that the human embryo is a person.. Last updated on 16 nov 2007 18:11:24 +0100..

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  • Title: Contact us
    Descriptive info: Antoine SUAREZ: suarez[at]leman[dot]ch.. Alfred DRIESSEN:.. Home Page.. Lorenzo DE VITTORI: lore[at]frenk[dot]com.. O.. Box 304.. CH-8044 Zurich.. Switzerland.. Sponsoring:.. You can efficiently contribute to promote the quantum culture.. by sponsoring the work of the Center for Quantum Philosophy.. We will be pleased to receive your gift in:.. CREDIT SUISSE.. 1211 Geneva 70 / Switzerland.. Account: 382084-00-4.. IBAN: CH94 0483 5038 2084 0000 4.. BIC: CRESCHZZ12A.. Last update on 8 jan 2008 08:35:23 +0100..

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  • Title: The Center for Quantum Philosophy - CFQP - The (visible) Team
    Descriptive info: From left: Wolfgang Tittel, Hugo Zbinden, Nicolas Gisin, Valerio Scarani, Antoine Suarez and André Stefanov.. close.. window to continue..

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