It continues to be alleged that superluminal in uences of any sort would be inconsistent with special relativity for the following three reasons: they would imply the existence of a ‘distinguished’ frame; they would allow the detection of absolute motion; and they would violate the relativity of simultaneity. This paper shows that the first two objections rest upon very elementary misunderstandings of Minkowski geometry and on lingering Newtonian intuitions about instantaneity. The third objection has a basis, but rather than (...) invalidating the notion of faster-than-light influences it points the way to more general conceptions of simultaneity that could allow for quantum nonlocality in a natural way. (shrink)

We discuss models that attempt to provide an explanation for the violation of Bell inequalities at a distance in terms of hidden influences. These models reproduce the quantum correlations in most situations, but are restricted to produce local correlations in some configurations. The argument presented in (Bancal et al. Nat Phys 8:867, 2012) applies to all of these models, which can thus be proved to allow for faster-than-light communication. In other words, the signalling character of these models cannot remain (...) hidden. (shrink)

This paper involves one crucial assumption; namely, that the statistical predictions of quantum mechanics for Bell's variant of the EPR experiment will continue to be verified as detector efficiencies are improved and the need for coincidence counters is eliminated. This assumption entails that any hidden-variables theory for quantum mechanics must violate Bell's inequality--the inequality derived in Bell (1964). It is shown here that four locality conditions are involved in the derivation of Bell's inequality; and that a violation of any of (...) the four locality conditions will either entail the existence of superluminal influences or the existence of superluminal signals (superluminal influences that can be used to transmit information), if conspiratorial theories can be ruled out. The attempts so far to rule out conspiratorial theories are all found to be rather dubious, but there are other considerations developed here that rule them out convincingly. Finally, it is demonstrated that violations of each of the four locality conditions can be used to transmit information superluminally, if certain auxiliary conditions are satisfied. This is of particular interest because one of these conditions corresponds to a condition dubbed "completeness" by Jon Jarrett. Jarrett and others have suggested that violations of completeness cannot be used to send information superluminally. Demonstrating otherwise is, perhaps, the most significant result obtained in this paper. (shrink)

It is a frequent assumption that—via superluminal information transfers—superluminal signals capable of enabling communication are necessarily exchanged in any quantum theory that posits hidden superluminal influences. However, does the presence of hidden superluminal influences automatically imply superluminal signalling and communication? The non-signalling theorem mediates the apparent conflict between quantum mechanics and the theory of special relativity. However, as a ‘no-go’ theorem there exist two opposing interpretations of the non-signalling constraint: foundational and operational. Concerning (...) Bell’s theorem, we argue that Bell employed both interpretations, and that he finally adopted the operational position which is associated often with ontological quantum theory, e.g., de Broglie–Bohm theory. This position we refer to as “effective non-signalling”. By contrast, associated with orthodox quantum mechanics is the foundational position referred to here as “axiomatic non-signalling”. In search of a decisive communication-theoretic criterion for differentiating between “axiomatic” and “effective” non-signalling, we employ the operational framework offered by Shannon’s mathematical theory of communication, whereby we distinguish between Shannon signals and non-Shannon signals. We find that an effective non-signalling theorem represents two sub-theorems: Non-transfer-control theorem, and Non-signification-control theorem. Employing NTC and NSC theorems, we report that effective, instead of axiomatic, non-signalling is entirely sufficient for prohibiting nonlocal communication. Effective non-signalling prevents the instantaneous, i.e., superluminal, transfer of message-encoded information through the controlled use—by a sender-receiver pair —of informationally-correlated detection events, e.g., in EPR-type experiments. An effective non-signalling theorem allows for nonlocal quantum information transfer yet—at the same time—effectively denies superluminal signalling and communication. (shrink)

We calculate the mixing of real and imaginary components of space and time under the influence of superluminal boosts in thex direction. A unique mixing is determined for this superluminal Lorentz transformation when we consider the symmetry properties afforded by the inclusion of three temporal directions. Superluminal transformations in complex six-dimensional space exhibit unique tachyonic connections which have both remote and local space-time event connections.

This chapter contains sections titled: The State of Play Particles and Relativistic Mass Increase Tachyons.

It is stressed that any theory of which it is claimed that it is compatible both with standard realism and with the experimental data is subject to severe constraints. One is that it must either incorporate superluminal influences or negate the free will of the experimentalist. The other one is that, in it. it is only at the price of accepting “backward causality” that a measurement can he interpreted as revealing the value the measured quantity had, just before, (...) rather than just after, the measurement look place. (shrink)

We present a quantum model for the motion of N point particles, implying nonlocal (i.e., superluminal) influences of external fields on the trajectories, that is nonetheless fully relativistic. In contrast to other models that have been proposed, this one involves no additional space-time structure as would be provided by a (possibly dynamical) foliation of space-time. This is achieved through the interplay of opposite microcausal and macrocausal (i.e., thermodynamic) arrows of time. PACS numbers 03.65.Ud; 03.65.Ta; 03.30.+p..

Stapp’s counterfactual argument for quantum nonlocality based upon a Hardy entangled state is shown to be flawed. While he has correctly analyzed a particular framework using the method of consistent histories, there are alternative frameworks which do not support his argument. The framework dependence of quantum counterfactual arguments, with analogs in classical counterfactuals, vitiates the claim that nonlocal (superluminal) influences exist in the quantum world. Instead it shows that counterfactual arguments are of limited use for analyzing these questions.

This chapter contains sections titled: Causation, Counterfactuals, and Laws Two World Pictures The EPR Argument A Note on Wave Collapse But is it Causation? Superluminal Influences and Relativity.

This thesis uses high-precision single-photon experiments to shed new light on the role of reality, causality, and uncertainty in quantum mechanics. It provides a comprehensive introduction to the current understanding of quantum foundations and details three influential experiments that significantly advance our understanding of three core aspects of this problem. The first experiment demonstrates that the quantum wavefunction is part of objective reality, if there is any such reality in our world. The second experiment shows that quantum correlations cannot be (...) explained in terms of cause and effect, even when considering superluminal influences between measurement outcomes. The final experiment in this thesis demonstrates a novel uncertainty relation for joint quantum measurements, where the textbook relation does not apply. (shrink)

Certain properties of the Bell-type correlations and, in particular, the impossibility of using them to transmit signals faster than light, are investigated from the point of view of the conceptual structure of quantum mechanics and of Whitehead's process philosophy. The collapses of quantum states are shown to correspond to perspectives of different frames of reference on a Whiteheadian process of self-creation of actual entities. The analysis suggests a fundamental limitation on the capacity to describe the propagation of influences among (...) the results of measurements at space-like separation. It is further shown that, if Whitehead's framework is modified in a specific way, it accounts very well for the apparent existence of superluminal influences, and for the impossibility of using them for superluminal communication. (shrink)

Quantum entanglement is widely believed to be a feature of physical reality with undoubted (though debated) metaphysical implications. But Schrödinger introduced entanglement as a theoretical relation between representatives of the quantum states of two systems. Entanglement represents a physical relation only if quantum states are elements of physical reality. So arguments for metaphysical holism or nonseparability from entanglement rest on a questionable view of quantum theory. Assignment of entangled quantum states predicts experimentally confirmed violation of Bell inequalities. Can one use (...) these experimental results to argue directly for metaphysical conclusions? No. Quantum theory itself gives us our best explanation of violations of Bell inequalities, with no superluminal causal influences and no metaphysical holism or nonseparability—but only if quantum states are understood as objective and relational, though prescriptive rather than ontic. Correct quantum state assignments are backed by true physical magnitude claims: but backing is not grounding. Quantum theory supports no general metaphysical holism or nonseparability; though a claim about a compound physical system may be significant and true while similar claims about its components are neither. Entanglement may well have have few, if any, first-order metaphysical implications. But the quantum theory of entanglement has much to teach the metaphysician about the roles of chance, causation, modality and explanation in the epistemic and practical concerns of a physically situated agent. (shrink)

Quantum entanglement is widely believed to be a feature of physical reality with undoubted metaphysical implications. But Schrödinger introduced entanglement as a theoretical relation between representatives of the quantum states of two systems. Entanglement represents a physical relation only if quantum states are elements of physical reality. So arguments for metaphysical holism or nonseparability from entanglement rest on a questionable view of quantum theory. Assignment of entangled quantum states predicts experimentally confirmed violation of Bell inequalities. Can one use these experimental (...) results to argue directly for metaphysical conclusions? No. Quantum theory itself gives us our best explanation of violations of Bell inequalities, with no superluminal causal influences and no metaphysical holism or nonseparability—but only if quantum states are understood as objective and relational, though prescriptive rather than ontic. Correct quantum state assignments are backed by true physical magnitude claims: but backing is not grounding. Quantum theory supports no general metaphysical holism or nonseparability; though a claim about a compound physical system may be significant and true while similar claims about its components are neither. Entanglement may well have have few, if any, first-order metaphysical implications. But the quantum theory of entanglement has much to teach the metaphysician about the roles of chance, causation, modality and explanation in the epistemic and practical concerns of a physically situated agent. (shrink)

L. Vervoort claims to have found a model which “can violate the Bell inequality and reproduce the quantum statistics, even if it is based on local dynamics only”. This claim is false. The proposed model contains global elements. The physics behind the model is local, but would not allow the explanation of violations of Bell inequalities for space-like separated events, if superluminal causal influences are forbidden. To use it for this purpose, one has to introduce a preferred frame (...) where information can be send faster than light. As a cause of the misunderstanding we identify the unfortunate convention to use “local” as a synonym for Einstein-local, so that theories which are local in every physically relevant sense have to be named “non-local”, and argue that this convention should be abandoned. (shrink)

Bell's theorem is expounded as an analysis in Bayesian inference. Assuming the result of a spin measurement on a particle is governed by a causal variable internal (hidden, “local”) to the particle, one learns about it by making a spin measurement; thence about the internal variable of a second particle correlated with the first; and from there predicts the probabilistic result of spin measurements on the second particle. Such predictions are violated by experiment: locality/causality fails. The statistical nature of the (...) observations rules out signalling; acausal, superluminal, or otherwise. Quantum mechanics is irrelevant to this reasoning, although its correct predictions of experiment imply that it has a nonlocal/acausal interpretation. Cramer's newtransactional interpretation, which incorporates this feature by adapting the Wheeler-Feynman idea of advanced and retarded processes to the quantum laws, is advocated. It leads to an invaluable way of envisaging quantum processes. The usual paradoxes melt before this, and one, the “delayed choice” experiment, is chosen for detailed inspection. Nonlocality implies practical difficulties in influencing hidden variables, which provides a very plausible explanation for why they have not yet been found; from this standpoint, Bell's theoremreinforces arguments in favor of hidden variables. (shrink)

The experimental evidence for electromagnetic signals propagating with superluminal group velocity is recalled. Transformations of space and time depending on a synchronization parameter, e1, indicate the existence of a privileged inertial system. The Lorentz transformations are obtained for a particular e1≠0. No standard experiment on relativity depends on e1, but if accelerations are considered only e1=0 remains possible. The causal paradox generated by superluminal signals (SLS) in the theory of relativity does not exist in the theory with e1=0. (...) The irrelevance of SLS for the Einstein, Podolsky and Rosen paradox is pointed out. (shrink)

A criterion is proposed to ensure that classical relativistic fields do not propagate superluminally. If this criterion does indeed serve as a sufficient condition for no superluminal propagation it follows that various other criteria found in the physics literature cannot serve as necessary conditions since they can fail although the proffered condition holds. The rejected criteria rely on energy conditions that are believed to hold for most classical fields used in actual applications. But these energy conditions are known to (...) fail at small scales for quantum fields. It is argued that such a failure is not necessarily a cause for concern about superluminal propagation in the quantum regime since the proffered criterion of no superluminal propagation for classical fields has a natural analog for quantum fields and, further, this quantum analog condition provably holds for some quantum fields despite the violation of energy conditions. The apparatus developed here also offers a different approach to treating the Reichenbach-Salmon cases of "pseudo-causal processes" and helps to clarify the issue of whether relativity theory is consistent with superluminal propagation. (shrink)

Special relativity is said to prohibit faster-than-light (superluminal) signaling, yet controversy regularly arises as to whether this or that physical phenomenon violates the prohibition. I argue that the controversy is a result of a lack of clarity as to what it means to ‘signal’, and I propose a criterion. I show that according to this criterion, superluminal signaling is not prohibited by special relativity.

We argue that any superluminal theory Tis empirically equivalent to a non-superluminaltheory T★, with thefollowing constraints onT★ : T★ preservesthe spacetime intervals between events as entailedby T, T★ is naturalistic (as longas T is), and all the events which have causesaccording to T also have causes according toT★. Tim Maudlin (1996) definesstandard interpretations of quantum mechanicsas interpretations `according to which there wasa unique set of outcomes in Aspect's laboratory,which outcomes occurred at spacelike separation’, andMaudlin claims that standard interpretations must (...) benon-local in the sense that there are superluminalinfluences. We show (even assuming Aspect's experimentis ideal) that Maudlin's claim is false. (shrink)

A superluminal signal velocity (i.e. faster than light) is said to violate causality. However, superluminal signal velocities have been measured in tunneling experiments recently. The classical dipole interaction approach by Sommerfeld and Brillouin results in a complex refractive index with a finite real part. For the tunneling process with its purely imaginary refractive index this model obtaines a zero-time traversing of tunneling barriers in agreement with wave meechanics. The information of a signal is proportional to the product of (...) its frequency band width and its time duration. The reasons that superluminal signal velocities do not violate causality are: (i) physical signals are frequency band limited and (ii) signals have a finite time duration. (shrink)

Superluminal particles are studied within the framework of the Extended Relativity theory in Clifford spaces (C-spaces). In the simplest scenario, it is found that it is the contribution of the Clifford scalar component π of the poly-vector-valued momentum which is responsible for the superluminal behavior in ordinary spacetime due to the fact that the effective mass $\mathcal{M} = \sqrt{ M^{2} - \pi^{2} }$ is imaginary (tachyonic). However, from the point of view of C-space, there is no superluminal (...) (tachyonic) behavior because the true physical mass still obeys M 2>0. Therefore, there are no violations of the Clifford-extended Lorentz invariance and the extended Relativity principle in C-spaces. It is also explained why the charged muons (leptons) are subluminal while its chargeless neutrinos may admit superluminal propagation. A Born’s Reciprocal Relativity theory in Phase Spaces leads to modified dispersion relations involving both coordinates and momenta, and whose truncations furnish Lorentz-violating dispersion relations which appear in Finsler Geometry, rainbow-metrics models and Double (deformed) Special Relativity. These models also admit superluminal particles. A numerical analysis based on the recent OPERA experimental findings on alleged superluminal muon neutrinos is made. For the average muon neutrino energy of 17 GeV, we find a value for the magnitude $|\mathcal{M } | = 119.7\mbox{~MeV}$ that, coincidentally, is close to the mass of the muon m μ =105.7 MeV. (shrink)

The theory of relativity forbids the superluminal travel of ordinary matter. However, it is possible to amend the theory of relativity and to develop a theory permitting superluminal travel. The acceptability of the features needed for superluminal travel is discussed.

In a previous paper a theoretical method permitting superluminal travel was suggested. A difficulty with the global conservation of energy and momentum is settled here.

It is a received view that superluminal signaling is prohibited in collapse theories of quantum mechanics. In this paper, I argue that this may be not the case. I propose two possible mechanisms of superluminal signaling in collapse theories. The first one is based on the well-accepted solution to the tails problem, and the second one is based on certain assumptions about the minds of observers. Finally, I also discuss how collapse theories can avoid such superluminal signaling.

Special relativity is said to prohibit faster-than-light (superluminal) signalling, yet controversy regularly arises as to whether this or that physical phenomenon violates the prohibition. I argue that the controversy is a result of a lack of clarity as to what it means to `signal', and I propose a criterion. I show that although we have no reason to think that one can send signals faster than light, this is not prohibited by special relativity.

In this article, after a theoretical introduction and a sketch of some related long-standing predictions, a bird's-eye view is presented—with the help of nine figures—of the various experimental sectors of physics in which Superluminal motions seem to appear (thus contributing support to those past predictions). In particular, a panorama is presented of the experiments with evanescent waves and/or tunnelling photons, and with the “localized Superluminal solutions” to the Maxwell equations (like the so-called X-shaped beams). The present review is (...) brief, but is followed by a large enough bibliography to allow the interested reader deepening the preferred topic. (shrink)

It is deeply entrenched dogma that relativity theory prohibits superluminal propagation. It is also experimentally well-established that under some circumstances, classical electromagnetic fields propagate through a dielectric medium with superluminal group velocities and superluminal phase velocities. But it is usually claimed that these superluminal velocities do not violate the relativistic prohibition. Here I analyze electromagnetic fields in a dielectric medium within a framework for understanding superluminal propagation recently developed by Geroch and elaborated by Earman. I (...) will argue that for some parameter values, electromagnetic fields do propagate superluminally in the Geroch-Earman sense. (shrink)

This book is a selection from the papers of the First International Conference on Superluminal Physics as New Fields of Research held at the University of New Mexico, Gallup Campus, USA, in July 2012. The editor have selected seven papers proposed by the following authors and co co-authors Kaizhe Guo Guo, Chongwu Guo Guo, Chen Jianguojianguo, Dong Jingfeng Jingfeng, Mi Haijiang Haijiang, Changwei Hu Hu, Yang Shijiashijia, Guli, and Fu Yuhua Yuhua.

A simple quantum relativistic model of ν µ − ντ neutrino oscillations in the OPERA experiment is presented. This model suggests that the two components in the neutrino beam are separated in space. After being created in a meson decay, the µ-neutrino moves 18 meters ahead of the beam’s center of energy, while the τ -neutrino is behind. Both neutrinos have subluminal speeds, however the advanced start of the ν µ explains why it arrives in the detector 60 ns earlier (...) than expected. Our model does violate the special-relativistic ban on superluminal signals. However, usual arguments about violation of causality are not applicable here. The invalidity of standard special-relativistic arguments is related to the interaction-dependence of the boost operator, which implies that boost-transformed space-time coordinates of events with interacting particles do not obey linear and universal Lorentz formulas. (shrink)

Automated influence is one of the most pervasive applications of artificial intelligence in our day-to-day lives, yet a thoroughgoing account of its associated individual and societal harms is lacking. By far the most widespread, compelling, and intuitive account of the harms associated with automated influence follows what I call the control argument. This argument suggests that users are persuaded, manipulated, and influenced by automated influence in a way that they have little or no control over. Based on evidence about the (...) effectiveness of targeted advertising as well as empirical results about the nature of attentional control, I provide reasons to reject this argument. In turn, I use C. Thi Nguyen’s theory of value collapse to develop a new account of the harmfulness of automated influence. (shrink)

Summary. — The following theorem is proved.: If the statistical predictions of quantum theory are true in general and. if the macroscopic world is not radically different from what is observed, then what happens macroscopically in one space-time region must in some cases depend on variables that are controlled by experimenters in far-away, space-like-separated. regions. By what happens macroscopically in one space-time region is meant specifically the occurrence or nonoccurrence of a macroscopic event, such as the d.etection and recording of (...) a particle by some macroscopic device. By a variable controlled. by an experimenter in a certain space-time region is meant specifically the experimental setting in that region of some macroscopic device, in which this setting is controlled. by an experimenter acting within that region. The theorem pertains speci6cally to experimental situations in which there .are two far-apart, spacelike-separated. regions in each of which there is a device that can be set at either of two alternative settings by an experimenter acting within ' that region. There. is also a long sequence of experimental results (4.e. events) in each of the two regions. The theorem asserts that, for some such cases, it is mathematically impossible, within the manifold. (shrink)

A tachyon or a superluminal wave group appears as a spacelike structure through a region in the reference frame in which it is at rest. Such a structure can arise from residue left (a) by a particle or wave group traveling at fundamental speed c or less, or (b) in the creation or separation of particles. Thus, Maund's argument does not prove that tachyons cannot exist. Creation may include lepton-quark production as well as particle-antiparticle production.

The relation between quantum collapse, consciousness and superluminal communication is analyzed. As we know, quantum collapse, if exists, can result in the appearance of quantum nonlocality, and requires the existence of a pre- ferred Lorentz frame. This may permit the realization of quantum superluminal communication (QSC), which will no longer result in the usual causal loop in case of the existence of a preferred Lorentz frame. The possibility of the existence of QSC is further analyzed under the assumption (...) that quantum collapse is a real process. We demonstrate that the combination of quantum collapse and the consciousness of the observer will permit the observer to distinguish nonorthogonal states in principle. This provides a possible way to realize QSC. Some implications of the existence of QSC are briefy discussed. (shrink)

A recent thought experiment to achieve superluminal signalling within the Pitowsky model is examined, and it is shown that such signalling is not possible. The analysis of the experiment is used to highlight the paradoxical nonphysical nature of Pitowsky's extended notion of probability.

Hud Hudson has recently suggested a scenario intended to show that, assuming the doctrine of temporal parts and a sufficiently liberal view of composition, there are material objects that move faster than light. I accept Hudson's conditional but contend that his modus ponens is less plausible that the corresponding modus tollens. Reversed in this way, the argument stemming from the scenario raises the cost of mereological liberalism and advances the case for a principled restriction on diachronic composition.

In the approximation that every inertial observer experiences a homogeneous, uniform flow of time and sees a space that is Euclidean, the arena of physics is Minkowskian and one speed is the same in all intertial frames. If a given intertial observer finds an infinitesimal source or particle traveling faster than this fundamental speed near a given event, the source must appear in some inertial frame spread over neighboring positions at a given time as a spacelike structure. If this structure (...) persists over a period of proper time, it can be interpreted as a wave group. If it is conserved, it can be interpreted as a line or tube of force. (shrink)

Jarrett has demonstrated that "strong locality," one of the conditions used by Bell to derive his well known inequality, is equivalent to the conjunction of two other conditions which he calls "hidden locality" and "completeness." He has also demonstrated that if it is possible to control the hidden states of the measured system, then violations of hidden locality can be used to transmit information superluminally; and that this is not so with respect to violations of completeness. This he has taken (...) to mean that it is not possible to use violations of completeness to do so under any circumstances. In this essay, it is argued that such violations can be used to do so, if one other condition is satisfied. (shrink)

The FLASH communicator consists of an apparatus which can distinguish between plane unpolarized (PUP) and circularly unpolarized (CUP) light plus a simple EPR arrangement. FLASH exploits the peculiar properties of “measurements of the Third Kind.” One purpose of this article is to focus attention on the operation of idealized laser gain tubes at the one-photon limit.

Bell (1964) demonstrated that if two restrictions are imposed on the hypothetical hidden variables supposed to underlie quantum mechanical states, then it is possible to derive an inequality that is violated by certain predictions of QM (Quantum Mechanics); the predictions concern pairs of systems whose states are strongly correlated. The two restrictions are denoted herein as SL (Strong Locality) and HA (Hidden Autonomy)1, and the inequality as BI (the Bell Inequality). Since SL and HA together entail BI, and QM violates (...) BI, it follows that any HVT (Hidden-Variables Theory) for QM must violate either SL or HA.It is well known that a condition known as PA (Perfect Anti-correlation) was also used by Bell to derive the inequality. PA says that parallel experiments (experiments with parallel spin-analyzer orientations) never yield the same results. (shrink)