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)

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)

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.

Experiments with evanescent modes and tunneling particles have shown that (i) their signal velocity may be faster than light, (ii) they are described by virtual particles, (iii) they are nonlocal and act at a distance, (iv) experimental tunneling data of phonons, photons, and electrons display a universal scattering time at the tunneling barrier front, and (v) the properties of evanescent, i.e. tunneling modes are not compatible with the special theory of relativity.

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)

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.

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)

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)

We consider the quantum electrodynamic problem of the velocity of transmission of an excitation from one atom to another, which was posed by Fermi in 1932 and, in an improved version, by Ferretti in 1968. The problem is solved using Heisenberg operators. The transmission velocity is shown to exceed the light velocity. We argue that this acausal result is to be explained by the inadmissibly idealized description of the signal source used by Fermi and Ferretti.

In this paper and its sequel, I consider the significance of Jarrett’s and Shimony’s analyses of the so-called factorisability condition for clarifying the nature of quantum non-locality. In this paper, I focus on four types of non-locality: superluminal signalling, action-at-a-distance, non-separability and holism. In the second paper, I consider a fifth type of non-locality: superluminal causation according to ‘logically weak’ concepts of causation, where causal dependence requires neither action nor signalling. In this connection, I pay special attention to (...) the difficulties that superluminal causation raises in relativistic space–time. I conclude by evaluating the relevance of Jarrett’s and Shimony’s analyses for clarifying the question of the compatibility of quantum non-locality with relativity theory. My main conclusions are, first: these analyses are significant for clarifying the questions of superluminal signalling in quantum phenomena and for the compatibility of these phenomena with relativity. But, second, by contrast: these analyses are not very significant for the study of action-at-a distance, superluminal causation, non-separability and holism in quantum phenomena. (shrink)

In this paper and its sequel, I consider the significance of Jarrett’s and Shimony’s analyses of the so-called factorisability condition for clarifying the nature of quantum non-locality. In this paper, I focus on four types of non-locality: superluminal signalling, action-at-a-distance, non-separability and holism. In the second paper, I consider a fifth type of non-locality: superluminal causation according to ‘logically weak’ concepts of causation, where causal dependence requires neither action nor signalling. In this connection, I pay special attention to (...) the difficulties that superluminal causation raises in relativistic space–time. I conclude by evaluating the relevance of Jarrett’s and Shimony’s analyses for clarifying the question of the compatibility of quantum non-locality with relativity theory. My main conclusions are, first: these analyses are significant for clarifying the questions of superluminal signalling in quantum phenomena and for the compatibility of these phenomena with relativity. But, second, by contrast: these analyses are not very significant for the study of action-at-a distance, superluminal causation, non-separability and holism in quantum phenomena. (shrink)

A macroscopic realization of the peculiar virtual particles is presented. The classical Helmholtz and the Schrödinger equations are differential equations of the same mathematical structure. The solutions with an imaginary wave number are called evanescent modes in the case of elastic and electromagnetic fields. In the case of non-relativistic quantum mechanical fields they are called tunneling solutions. The imaginary wave numbers point to strange consequences: The waves are non-local, they are not observable, and they are described as virtual particles. During (...) the last two decades QED calculations of the solutions with an imaginary wave number have been experimentally confirmed for phonons, photons, and electrons. The experimental proofs of the predictions of non-relativistic quantum mechanics and the Wigner phase time approach for the elastic, electromagnetic and Schrödinger fields will be presented in this article. The results are zero time in the barrier and an interaction time (i.e. a phase shift) at the barrier interfaces. The measured tunneling time scales approximately inversely with the particle energy. Actually, the tunneling time is given only by the barrier boundary interaction time, as zero time is spent inside a barrier. (shrink)

Fifty years ago Hartman studied the barrier transmission time of wave packets (J Appl Phys 33:3427–3433, 1962). He was inspired by the tunneling experiments across thin insulating layers at that time. For opaque barriers he calculated faster than light propagation and a transmission time independent of barrier length, which is called the Hartman effect. A faster than light (FTL or superluminal) wave packet velocity was deduced in analog tunneling experiments with microwaves and with infrared light thirty years later. (...) Recently, the conjectured zero time of electron tunneling was claimed to have been observed in ionizing helium inside the barrier. The calculated and measured short tunneling time arises at the barrier front. This tunneling time was found to be universal for elastic fields as well as for electromagnetic fields. Remarkable is that the delay time is the same for the reflected and the transmitted waves in the case of symmetric barriers. Several theoretical physicists predicted this strange nature of the tunneling process. However, even with this background many members of the physics community do not accept a FTL signal velocity interpretation of the experimental tunneling results. Instead a luminal front velocity was calculated to explain the FTL experimental results frequently. However, Brillouin stated in his book on wave propagation and group velocity that the front velocity is given by the group velocity of wave packets in the case of physical signals, which have only finite frequency bandwidths. Some studies assumed barriers to be cavities and the observed tunneling time does represent the cavity lifetime. We are going to discus these continuing misleading interpretations, which are found in journals and in textbooks till today. (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.

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)

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)

In order to improve the accuracy and reliability of wireless location in NLOS environment, a wireless location algorithm based on artificial neural network is proposed for NLOS positioning error caused by non-line-of-sight propagation, such as occlusion and signal reflection. The mapping relationship between TOA and TDOA measurement data and coordinates is established. The connection weights of neural network are estimated as the state variables of nonlinear dynamic system. The multilayer perceptron network is trained by the real-time neural network training (...) algorithm based on extended Kalman. Combined with the statistical characteristics of NLOS error, the state component NLOS bias estimation is modified to realize TDOA data reconstruction. Simulation and experimental data analysis show that the algorithm can effectively weaken the influence of NLOS error. The localization method does not depend on the specific NLOS error distribution, nor does it need LOS and NLOS recognition. It can significantly improve the mobile positioning accuracy. (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.

The 1964 theorem of John Bell shows that no model that reproduces the predictions of quantum mechanics can simultaneously satisfy the assumptions of locality and determinism. On the other hand, the assumptions of signal locality plus predictability are also sufficient to derive Bell inequalities. This simple theorem, previously noted but published only relatively recently by Masanes, Acin and Gisin, has fundamental implications not entirely appreciated. Firstly, nothing can be concluded about the ontological assumptions of locality or determinism independently of (...) each other—it is possible to reproduce quantum mechanics with deterministic models that violate locality as well as indeterministic models that satisfy locality. On the other hand, the operational assumption of signal locality is an empirically testable (and well-tested) consequence of relativity. Thus Bell inequality violations imply that we can trust that some events are fundamentally unpredictable, even if we cannot trust that they are indeterministic. This result grounds the quantum-mechanical prohibition of arbitrarily accurate predictions on the assumption of no superluminal signalling, regardless of any postulates of quantum mechanics. It also sheds a new light on an early stage of the historical debate between Einstein and Bohr. (shrink)

The experimental situation proposed by Fisk consists of a light source in a system S which sends a signal to two observers, one located at a distance x1 from the source and at rest in S, and the other moving away from the source at a speed v, in such a manner that its position coincides with the point x1 when the light signal reaches x1. The moving observer's coordinate system may be designated as S'. Further, it is (...) assumed that there is a half-silvered mirror associated with the moving observer, and that the light signal reaches the mirror so that part of the signal is received by the S' observer and part is received by the stationary S observer; each observer considers the light to reach him when he is at point x1. (shrink)

In a preceding paper, I studied the significance of Jarrett's and Shimony's analyses of 'factorisability' into 'parameter independence' and 'outcome independence' for clarifying the nature of non-locality in quantum phenomena. I focused on four types of non-locality; superluminal signalling, action-at-a-distance, non-separability and holism. In this paper, I consider a fifth type of non-locality: superluminal causation according to 'logically weak' concepts of causation, where causal dependence requires neither action nor signalling. I conclude by considering the compatibility of non-factorisable theories (...) with relativity theory. In this connection, I pay special attention to the difficulties that superluminal causation raises in relativistic spacetime. My main findings in this paper are: first, parameter-dependent and outcome-dependent theories both involve superluminal causal connections between outcomes and between settings and outcomes. Second, while relativistic deterministic parameter-dependent theories seem impossible on pain of causal paradoxes, relativistic indeterministic parameter-dependent theories are not subjected to the same challenge. Third, current relativistic non-factorisable theories seem to have some rather unattractive characteristics. (shrink)

This chapter contains sections titled: A Slightly Technical Interlude3 Bell's Theorem Again What Does Factorization Signify? Relativity and Signals Signaling Paradoxes Appendix B: Bohmian Mechanics.

The central nervous system uses feedback processes that occur at multiple time scales to control interactions with the environment. The long-latency response is the fastest process that directly involves cortical areas, with a motoneuron response measurable 50 ms following an imposed limb displacement. Several behavioral factors concerning perturbation mechanics and the active role of muscles prior or during the perturbation can modulate the long-latency response amplitude in the upper limbs, but the interactions among many of these factors had not been (...) systematically studied before. We conducted a behavioral study on thirteen healthy individuals to determine the effect and interaction of four behavioral factors – background muscle torque, perturbation direction, perturbation velocity, and task instruction – on the LLRa evoked from the flexor carpi radialis and extensor carpi ulnaris muscles after velocity-controlled wrist displacements. The effects of the four factors were quantified using both a 0D statistical analysis on the average perturbation-evoked EMG signal in the period corresponding to an LLR, and using a timeseries analysis of EMG signals. All factors significantly modulated LLRa, and their combination nonlinearly contributed to modulating the LLRa. Specifically, all the three-way interaction terms that could be computed without including the interaction between instruction and velocity significantly modulated the LLR. Analysis of the three-way interaction terms of the 0D model indicated that for the ECU muscle, the LLRa evoked when subjects are asked to maintain their muscle activation in response to the perturbations was greater than the one observed when subjects yielded to the perturbations, but this effect was not measured for muscles undergoing shortening or in absence of background muscle activation. Moreover, higher perturbation velocity increased the LLRa evoked from the stretched muscle in presence of a background torque, but no effects of velocity were measured in absence of background torque. Also, our analysis identified significant modulations of LLRa in muscles shortened by the perturbation, including an interaction between torque and velocity, and an effect of both torque and velocity. The time-series analysis indicated the significance of additional transient effects in the LLR region for muscles undergoing shortening. (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.

A number of physical processes and experimental procedures are listed which appear to be inexplicable in the context of the conventionality thesis of Reichenbach and Grünbaum. Distant synchrony can be produced by procedures based on the free displacement or rotation of elastic solids. Results are expected to agree with Einstein's definition of distant synchrony (by means of light signals, assuming isotropy). The one-way velocity of light can be measured using a rotating shaft, slotted disks, and one stationary clock.

It is shown that (a) both the dispersion relations between the mean frequency θ0 and the mean wave number k 0 are invariant under the Lorentz transformation; and (b) the relativistic Doppler effects on θ 0 and k 0 differ. In the suboptic packet there is anomalous red shift in the mean wave number k' 0 received from a source receding with speed v: k′ 0 changes sign through zero as v goes through the value vg, the mean group (...) class='Hi'>velocity in the packet. In the superoptic packet the anomalous red shift is in the mean frequency θ′ 0 which reverses sign through zero as v goes through the value vp, the mean phase velocity in the packet. This last finding indicates a blackout of the superoptic signal when propagated toward a receiver moving away from the source at a speed greater than vp. There is no violation of causality involved, and the final conclusion of the paper is that it is not a fundamental axiom of “special relativity,” as usually believed, to deny that information can be transmitted at speeds greater than c. (shrink)

We derive the equation describing the flow of a variable current in straight wires and in coaxial cables from Newton's second law of motion plus Weber's electrodynamics. We show that in both cases the signal propagates at light velocity.

The principal goal of the brain-computer interface is to translate brain signals into meaningful commands to control external devices or neuroprostheses to restore lost functions of patients with severe motor disabilities. The invasive recording of brain signals involves numerous health issues. Therefore, BCIs based on non-invasive recording modalities such as electroencephalography are safer and more comfortable for the patients. The BCI requires reconstructing continuous movement parameters such as position or velocity for practical application of neuroprostheses. The BCI studies in (...) continuous decoding have extensively relied on extracting features from the amplitude of brain signals, whereas the brain connectivity features have rarely been explored. This study aims to investigate the feasibility of using phase-based connectivity features in decoding continuous hand movements from EEG signals. To this end, the EEG data were collected from seven healthy subjects performing a 2D center-out hand movement task in four orthogonal directions. The phase-locking value and magnitude-squared coherence are exploited as connectivity features along with multiple linear regression for decoding hand positions. A brute-force search approach is employed to find the best channel pairs for extracting features related to hand movements. The results reveal that the regression models based on PLV and MSC features achieve the average Pearson correlations of 0.43 ± 0.03 and 0.42 ± 0.06, respectively, between predicted and actual trajectories over all subjects. The delta and alpha band features have the most contribution in regression analysis. The results also demonstrate that both PLV and MSC decoding models lead to superior results on our data compared to two recently proposed feature extraction methods solely based on the amplitude or phase of recording signals. This study verifies the ability of PLV and MSC features in the continuous decoding of hand movements with linear regression. Thus, our findings suggest that extracting features based on brain connectivity can improve the accuracy of trajectory decoder BCIs. (shrink)

Although the popularity of Humane Education Programs as a method of teaching compassion and caring for all living beings is increasing, there is a need for rigorous, methodologically sound research evaluating the efficacy of HEP. Recent calls for the inclusion of HEP within broader humanistic, environmental, and social justice frameworks underline the importance of HEP beyond a simple “treatment of animals” model. Lack of methodological rigor in the majority of published HEP studies and dispersal across disparate fields , however, means (...) that there is a potential for the popular use of HEP to outstrip our understanding of the variables that impact efficacy. The current study discusses some of these issues and presents a pilot study of a literature-only HEP intervention. Comparisons with an age-matched control group indicated that the four-week HEP resulted in an increase in measures of empathy and treatment of animals, although only the increase in empathy levels was significant. This paper discusses the implications of the current results and areas in need of future consideration. (shrink)

Paramedics encounter ethical dilemmas at work, and while previous research has improved ethics education and practice, more can be learned from the lived experience of paramedics facing ethical challenges. This paper explores the lived experience of two paramedics, one with five years’ experience, the other twenty, presented with comparable cases. The participants, who were interviewed in a broader qualitative study exploring practical wisdom, were asked to select a case involving ethical decision-making from their own practice experience. Semi-structured interviews employed the (...) five-step Critical Decision Method as a framework to explore various aspects of the decision-making process. The two cases were identified as exemplars of prominent themes suitable for discussion. The findings highlighted several factors that influence paramedic ethical decision-making, including practical wisdom, communication and teamwork, clinical support, and education. This case comparison identifies a greater need to focus education on the fostering of practical wisdom, and the development of non-technical skills such as communication and teamwork, supported by interprofessional education endeavours. Furthermore, greater access to support for paramedics must be available to further evolve practical wisdom. The combination of improved education and support will likely cater for the full spectrum of ethical challenges faced by paramedics in their work. (shrink)

Although the popularity of Humane Education Programs as a method of teaching compassion and caring for all living beings is increasing, there is a need for rigorous, methodologically sound research evaluating the efficacy of HEP. Recent calls for the inclusion of HEP within broader humanistic, environmental, and social justice frameworks underline the importance of HEP beyond a simple “treatment of animals” model. Lack of methodological rigor in the majority of published HEP studies and dispersal across disparate fields , however, means (...) that there is a potential for the popular use of HEP to outstrip our understanding of the variables that impact efficacy. The current study discusses some of these issues and presents a pilot study of a literature-only HEP intervention. Comparisons with an age-matched control group indicated that the four-week HEP resulted in an increase in measures of empathy and treatment of animals, although only the increase in empathy levels was significant. This paper discusses the implications of the current results and areas in need of future consideration. (shrink)

This study examines the practices of Equine Assisted Therapy and Learning in Australia. Among Equine Assisted Therapy and Equine Assisted Learning centers there is a large degree of variation in practice worldwide. The current study outlines a range of practices in two states in Australia whereeatandealhave arisen and evolved from models developed elsewhere. The philosophical foundations, training and certification processes followed along with the types and training of horses involved are compared across facilities. The findings of the study illustrated the (...) large variation ineatandealin current practice in Australia. The results suggested that if the practices ofeatandealare to move out of the “fringe” of mental health and learning professional practice and into the mainstream, their theoretical underpinnings, certification and licensure procedures, and methodology of practice must become more clearly defined. (shrink)

In Australia, paramedics are obliged to practice ethically. Graduates of baccalaureate degrees in paramedicine should therefore possess a common grounding in ethics to meet the professional capabilities expected of registered paramedics. However, there is a lack of clarity regarding ethics education for paramedicine students, including what is taught, how it is taught, and how it is assessed. This paper explores ethics education for paramedicine students in Australia, how it aligns with current professional expectations, and how it may be enhanced. Point-in-time (...) data regarding ethics education was collected from websites of fifteen Australian universities offering undergraduate baccalaureate degrees in paramedicine. Data collection was supported by consultation with academics from several institutions. Content analysis was utilised to categorise and analyse data to explore similarities and differences in curricula. Similarities included approaches to learning and teaching and the use of case-based learning, with variability found across teaching staff profiles and content areas. Findings suggest it is time for collaboration to develop a model ethics curriculum for paramedicine students in Australia. (shrink)

A physical theory of experiments carried out in a space-time region can accommodate a detector localized in another space-like separated region, in three, not necessarily exclusive, ways: (1) the detector formally collapses physical states across space-like separations, (2) the detector enables superluminal signals, and (3) the theory becomes logically inconsistent. If such a theory admits autonomous evolving states, the space-like collapse must be instantaneous. Time-like separation does not allow such conclusions. We also prove some simple results on structural stability: (...) within the set of all possible theories, under a weak empirical topology, the set of all theories with superluminal signals and the set of all theories with retrograde signals are both open and dense. (shrink)

A simple model of a quantum clock is applied to the old and controversial problem of how long a particle takes to tunnel through a quantum barrier. The model has the advantage of yielding sensible results for energy eigenstates and does not require the use of time-dependent wave packets. Although the treatment does not forbid superluminal tunneling velocities, there is no implication of faster-than-light signaling because only the transit duration is measurable, not the absolute time of transit. A comparison (...) is given with the weak-measurement post-selection calculations of Steinberg. (shrink)

Arguments by Sorkin (Impossible measurements on quantum fields. In: Directions in general relativity: proceedings of the 1993 International Symposium, Maryland, vol 2, pp 293–305, 1993) and Borsten et al. (Phys Rev D 104(2), 2021. https://doi.org/10.1103/PhysRevD.104.025012 ) establish that a natural extension of quantum measurement theory from non-relativistic quantum mechanics to relativistic quantum theory leads to the unacceptable consequence that expectation values in one region depend on which unitary operation is performed in a spacelike separated region. Sorkin [ 1 ] labels (...) such scenarios ‘impossible measurements’. We explicitly present these arguments as a no-go result with the logical form of a reductio argument and investigate the consequences for measurement in quantum field theory (QFT). Sorkin-type impossible measurement scenarios clearly illustrate the moral that Microcausality is not by itself sufficient to rule out superluminal signalling in relativistic quantum theories that use Lüders’ rule. We review three different approaches to formulating an account of measurement for QFT and analyze their responses to the ‘impossible measurements’ problem. Two of the approaches are: a measurement theory based on detector models proposed in Polo-Gómez et al. (Phys Rev D, 2022. https://doi.org/10.1103/physrevd.105.065003 ) and a measurement framework for algebraic QFT proposed in Fewster and Verch (Commun Math Phys 378(2):851–889, 2020). Of particular interest for foundations of QFT is that they share common features that may hold general morals about how to represent measurement in QFT. These morals are about the role that dynamics plays in eliminating ‘impossible measurements’, the abandonment of the operational interpretation of local algebras \({\mathcal {A}}(O)\) as representing possible operations carried out in region _O_, and the interpretation of state update rules. Finally, we examine the form that the ‘impossible measurements’ problem takes in histories-based approaches and we discuss the remaining challenges. (shrink)

This note aims to make more familiar to philosophers yet another bizarre quantum mechanical effect with disturbing metaphysical implications. It is possible to modify the classic double-slit experiment so that one can register the path of a particle to determine which slit it passes through, and then erase this registered information so that the interference effects which would normally disappear upon registration of the "which path" information are reconstituted. Thus the "trajectory" of particles can be effected by temporally and spatially (...) distant operations on the slit detectors. Nonetheless, no untoward effects (such as superluminal signalling) can result from the operation of the eraser. (shrink)

Special relativity theory is generalized to two or more “maximal” signalling speeds. This framework is discussed in three contexts: (i) as a scenario for superluminal signalling and motion, (ii) as the possibility of two or more “light” cones due to the a “birefringent” vacuum, and (iii) as a further extension of conventionality beyond synchrony.

Jarrett (1984) and Ballentine and Jarrett (1987) have argued that violations of Jarrett's locality condition are strictly forbidden by the theory of relativity. In Ballentine and Jarrett, this claim is supported by an appeal to the fact that superluminal signalling gives rise to causal paradoxes. In this paper, it is argued that if violations of locality are permitted, certain puzzles indeed arise. The result takes the form of a set of apparent "no go" theorems. However, it is argued that (...) the results may not really show what they seem to, and that contrary to Ballentine and Jarrett, it is by no means clear that relativity forbids violations of Jarrett's locality condition. (shrink)

The dynamics-from-permutations of classical Ising spins is generalized here for an arbitrarily long chain. This serves as an ontological model with discrete dynamics generated by pairwise exchange interactions defining the unitary update operator. The model incorporates a finite signal velocity and resembles in many aspects a discrete free field theory. We deduce the corresponding Hamiltonian operator and show that it generates an exact terminating Baker–Campbell–Hausdorff formula. Motivation for this study is provided by the Cellular Automaton Interpretation of Quantum (...) Mechanics. We find that our ontological model, which is classical and deterministic, appears as if of quantum mechanical kind in an appropriate formal description. However, it is striking that small deformations of the model turn it into a genuine quantum theory. This supports the view that quantum mechanics stems from an epistemic approach handling physical phenomena. (shrink)

An apparent inadequacy of the velocity addition theorem in handling a Fizeau (like) experiment beyond the resonance frequence is shown not to be a true failing. The proof consists in showing that the invariance of the signal velocity is unrelated to its maximality. Next, Lorentz transformations which connect frames moving with supersignal velocity to those of subsignal velocity are derived, taking a cue from the acoustic case. Methods are also suggested for laboratory verification of the (...) theory. (shrink)

Signal causality, the prohibition of superluminal information transmission, is the fundamental property shared by quantum measurement theory and relativity, and it is the key to understanding the connection between nonlocal measurement effects and elementary interactions. To prevent those effects from transmitting information between the generating and observing process, they must be induced by the kinds of entangling interactions that constitute measurements, as implied in the Projection Postulate. They must also be nondeterministic as reflected in the Born Probability Rule. (...) The nondeterminism of entanglement-generating processes explains why the relevant types of information cannot be instantiated in elementary systems, and why the sequencing of nonlocal effects is, in principle, unobservable. This perspective suggests a simple hypothesis about nonlocal transfers of amplitude during entangling interactions, which yields straightforward experimental consequences. (shrink)