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Theoretical physicist focusing on foundations of quantum mechanics.edit
The formalism for computing the signal-to-noise ratio (SNR) for laser radar is reviewed and applied to the tasks of target detection, direction-finding, and phase change estimation with squeezed light. The SNR for heterodyne detection of... more
The formalism for computing the signal-to-noise ratio (SNR) for laser radar is reviewed and applied to the tasks of target detection, direction-finding, and phase change estimation with squeezed light. The SNR for heterodyne detection of co- herent light using a squeezed local oscillator is lower than that obtained using a coherent local oscillator. This is true for target detection, for phase estimation, and for direction-finding with a split detector. Squeezing the local oscillator also lowers SNR in balanced homodyne and heterodyne detection of coherent light. Loss places an upper bound on the improvement that squeezing can bring to direct-detection SNR.
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We obtain an expression for the one-loop effective potential coming from quantum fluctuations of massless scalars and spin-(1/2 fermions in a higher-dimensional manifold of product form Mâ´ x S/sup M/ x S/sup N/. In contrast with... more
We obtain an expression for the one-loop effective potential coming from quantum fluctuations of massless scalars and spin-(1/2 fermions in a higher-dimensional manifold of product form Mâ´ x S/sup M/ x S/sup N/. In contrast with previous calculations, we consider the case in which the total number of dimensions is even, since this is the relevant case for superstring compactification. A detailed calculation for a ten-dimensional spacetime with two internal three-spheres is performed, and an approximate static solution for the geometry is found, with the two internal radii being of the order of the Planck length for a sufficiently large number of matter fields. We study the stability of this solution and make some remarks on the possible cosmological implications of our results.
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We investigate the use of the fuzzy ARTMAP neural network for automatic classification of targets based on their radar range profiles. Tests on synthetic data indicate that fuzzy ARTMAP can yield substantial savings in memory requirements... more
We investigate the use of the fuzzy ARTMAP neural network for automatic classification of targets based on their radar range profiles. Tests on synthetic data indicate that fuzzy ARTMAP can yield substantial savings in memory requirements when compared to k nearest neighbor (kNN) classifiers. The performance of both types of classifiers is significantly improved by the use of multiwavelength profiles.
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Research Interests:
Neuroscience, Psychology, Cognitive Science, Electrophysiology, Life Sciences, and 15 moreMedicine, Brain Mapping, Cerebral Cortex, Orientation, Animals, Receptive Field, Complex Cell, Neurons, Second Order, Macaque, Macaca fascicularis, Medicine and Health Sciences, Neurosciences, Neural Network Model, and photic stimulation
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Physics, Theoretical Physics, Quantum Physics, Quantum Mechanics, Quantum Field Theory, and 8 moreLocality, Counterfactual Thinking, Interpretation of Quantum Mechanics, Philosophy and Religious Studies, Mathematical Sciences, Quantum nonlocality, Physical sciences, and Interpretations of Quantum Mechanics
The quantum search algorithm of Chen and Diao, which finds with certainty a single target item in an unsorted database, is modified so as to be capable of searching for an arbitrary specified number of target items. If the number of... more
The quantum search algorithm of Chen and Diao, which finds with certainty a single target item in an unsorted database, is modified so as to be capable of searching for an arbitrary specified number of target items. If the number of targets, nu_0, is a power of four, the new algorithm will with certainty find one of the targets in a database of n items using (1/2)(3(N/nu_0)^{log_base_4(3)}-1) \approx (1/2)(3(N/nu_0)^{0.7925}-1) oracle calls, where N is the smallest power of four greater than or equal to n. If nu_0 is not a power of four, the algorithm will, with a probability of at least one-half, find one of the targets using no more than (1/2)(9(N/nu)^{log_base_4(3)}-1) calls, where nu is the smallest power of four greater than or equal to nu_0.
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Stapp claims that, when spatial degrees of freedom are taken into account, Everett quantum mechanics is ambiguous due to a "core basis problem." To examine an aspect of this claim I generalize the ideal measurement model to... more
Stapp claims that, when spatial degrees of freedom are taken into account, Everett quantum mechanics is ambiguous due to a "core basis problem." To examine an aspect of this claim I generalize the ideal measurement model to include translational degrees of freedom for both the measured system and the measuring apparatus. Analysis of this generalized model using the Everett interpretation in the Heisenberg picture shows that it makes unambiguous predictions for the possible results of measurements and their respective probabilities. The presence of translational degrees of freedom for the measuring apparatus affects the probabilities of measurement outcomes in the same way that a mixed state for the measured system would. Examination of a measurement scenario involving several observers illustrates the consistency of the model with perceived spatial localization of the measuring apparatus.
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ARTMAP-FD extends fuzzy ARTMAP to perform familiarity discrimination. That is, the network learns to abstain from meaningless guesses on patterns not belonging to a class represented in the training set. ARTMAP-FD can also be applied in... more
ARTMAP-FD extends fuzzy ARTMAP to perform familiarity discrimination. That is, the network learns to abstain from meaningless guesses on patterns not belonging to a class represented in the training set. ARTMAP-FD can also be applied in conjunction with sequential evidence accumulation. Its performance is illustrated here on simulated radar range profile data
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302 Rubin 1. INTRODUCTION In the paper in which he introduces what has come to be known as the Everett or many-worlds interpretation of quantum mechanics, Ev-erett [1] states that "fictitious paradoxes like that of Einstein,... more
302 Rubin 1. INTRODUCTION In the paper in which he introduces what has come to be known as the Everett or many-worlds interpretation of quantum mechanics, Ev-erett [1] states that "fictitious paradoxes like that of Einstein, Podolsky, and Rosen which are concerned with ... ...
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Recently it has been shown that transformations of Heisenberg-picture operators are the causal mechanism which allows Bell-theorem-violating correlations at a distance to coexist with locality in the Everett interpretation of quantum... more
Recently it has been shown that transformations of Heisenberg-picture operators are the causal mechanism which allows Bell-theorem-violating correlations at a distance to coexist with locality in the Everett interpretation of quantum mechanics. A calculation to first order in perturbation theory of the generation of EPRB entanglement in nonrelativistic fermionic field theory in the Heisenberg picture illustrates that the same mechanism leads to correlations without nonlocality in quantum field theory as well. An explicit transformation is given to a representation in which initial-condition information is transferred from the state vector to the field operators, making the locality of the theory manifest.
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The usual interpretational rule of quantum mechanics which states that outcomes do not occur when their weights are zero is changed so as to preclude outcomes with weights less than a small but positive value. With this "positive... more
The usual interpretational rule of quantum mechanics which states that outcomes do not occur when their weights are zero is changed so as to preclude outcomes with weights less than a small but positive value. With this "positive preclusion" rule, and in the absence of any notion of objective probability, Everett quantum mechanics has the explanatory power to account for the evolution of organisms with subjective expectations of probability that are in accord with the Born rule. Positive preclusion also allows for the derivation of a connection between weight and relative frequency in situations involving a finite number of measurements.
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The presence of loss limits the precision of an approach to phase measurement using maximally entangled states, also referred to as NOON states. A calculation using a simple beam-splitter model of loss shows that, for all nonzero values L... more
The presence of loss limits the precision of an approach to phase measurement using maximally entangled states, also referred to as NOON states. A calculation using a simple beam-splitter model of loss shows that, for all nonzero values L of the loss, phase measurement precision degrades with increasing number N of entangled photons for N sufficiently large. For L above a critical value of approximately 0.785, phase measurement precision degrades with increasing N for all values of N. For L near zero, phase measurement precision improves with increasing N down to a limiting precision of approximately 1.018L radians, attained at N approximately equal to 2.218/L, and degrades as N increases beyond this value. Phase measurement precision with multiple measurements and a fixed total number of photons N{sub T} is also examined. For L above a critical value of approximately 0.586, the ratio of phase measurement precision attainable with NOON states to that attainable by conventional metho...
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A model for measurement in collapse-free nonrelativistic fermionic quantum field theory is presented. In addition to local propagation and effectively-local interactions, the model incorporates explicit representations of localized... more
A model for measurement in collapse-free nonrelativistic fermionic quantum field theory is presented. In addition to local propagation and effectively-local interactions, the model incorporates explicit representations of localized observers, thus extending an earlier model of entanglement generation in Everett quantum field theory [M. A. Rubin, Found. Phys. 32, 1495-1523 (2002)]. Transformations of the field operators from the Heisenberg picture to the Deutsch-Hayden picture, involving fictitious auxiliary fields, establish the locality of the model. The model is applied to manifestly-local calculations of the results of measurements, using a type of sudden approximation and in the limit of massive systems in narrow-wavepacket states. Detection of the presence of a spin-1/2 system in a given spin state by a freely-moving two-state observer illustrates the features of the model and the nonperturbative computational methodology. With the help of perturbation theory the model is appli...