Consecutive measurements performed on the same quantum system can reveal fundamental insights into quantum theory’s causal structure, and probe different aspects of the quantum measurement problem. According to the Copenhagen interpretation, measurements affect the quantum system in such a way that the quantum superposition collapses after each measurement, erasing any memory of the prior state. We show here that counter to this view, un-amplified measurements have coherent ancilla density matrices that encode the memory of the entire set of quantum measurements (...) that came before, and that the chain of this entire set is therefore non-Markovian. In contrast, sequences of amplified measurements are equivalent to a quantum Markov chain. We argue that the non-Markovian nature of quantum measurement has empirical consequences that are incompatible with the assumption of wave function collapse, thus elevating the collapse assumption into a testable hypothesis. Finally, we find that all of the information necessary to reconstruct an arbitrary non-Markovian quantum chain of measurements is encoded on the boundary of that chain, reminiscent of the holographic principle. (shrink)

In 1885, during initial discussions of J. C. Maxwell's celebrated thermodynamic demon, Whiting (1) observed that the demon-like velocity selection of molecules can occur in a gravitationally bound gas. Recently, a gravitational Maxwell demon has been proposed which makes use of this observation [D. P. Sheehan, J. Glick, and J. D. Means, Found. Phys. 30, 1227 (2000)]. Here we report on numerical simulations that detail its microscopic phase space structure. Results verify the previously hypothesized mechanism of its paradoxical behavior. This (...) system appears to be the only example of a fully classical mechanical Maxwell demon that has not been resolved in favor of the second law of thermodynamics. (shrink)

Some philosophers have attempted to utilize the conceptual tools of ethics in order to understand epistemology. One instantiation of this understands justification in terms of having a certain kind of epistemic right, namely, a right to believe. In variations of this theme, some hold that justification involves having the authority to believe, or being entitled to believe. But by examining the putative analogies between different versions of rights and justification, I demonstrate that justification should not be understood as having a (...) right to believe. (shrink)

In 1885, during initial discussions of J. C. Maxwell's celebrated thermodynamic demon, Whiting(1) observed that the demon-like velocity selection of molecules can occur in a gravitationally bound gas. Recently, a gravitational Maxwell demon has been proposed which makes use of this observation [D. P. Sheehan, J. Glick, and J. D. Means, Found. Phys. 30, 1227 (2000)]. Here we report on numerical simulations that detail its microscopic phase space structure. Results verify the previously hypothesized mechanism of its paradoxical behavior. This system (...) appears to be the only example of a fully classical mechanical Maxwell demon that has not been resolved in favor of the second law of thermodynamics. (shrink)

The current debate on recreational drug policy is roughly a contest between prohibition advocates and legalization advocates. This paper offers a third alternative that is a compromise between those two. The centralized-use compromise can secure the autonomy interests that are important to defenders of legalization, and it can prevent harms to others that are the focus of prohibition arguments. The centralized-use compromise also offers a possible way to reduce the black market while also reducing the rate of addiction and the (...) associated debasing harms to self. (shrink)

A traditional line of inquiry in epistemology tried to analyze the concept of knowledge into its constituent components. In virtue of understanding these alleged more basic concepts, such as truth, justification, and belief, it was hoped that a complete and informative theory of knowledge would emerge. According to the revolutionary approach advocated here, one which originates in Timothy Williamson's Knowledge and Its Limits, better success can be achieved by reversing this conceptual analysis structure by taking knowledge as the fundamental explanatory (...) tool in epistemological theorizing. I defend the view that this knowledge-theoretic approach exceeds the explanatory value of its conceptual analysis competitor in the sense that the best explanations of epistemologically significant phenomena are appropriately expressed in terms of knowledge per se. (shrink)

A new member of a growing class of unresolved second law paradoxes is examined.(1–7) In a sealed blackbody cavity, a spherical gravitator is suspended in a low density gas. Infalling gas suprathermally strikes the gravitator which is spherically asymmetric between its hemispheres with respect to surface trapping probability for the gas. In principle, this system can be made to perform steady-state work solely at the expense of heat from the heat bath, this in apparent violation of the second law of (...) thermodynamics. Detailed three-dimensional test particle simulations of this system support this prediction. Standard resolutions to the paradox are discussed and found to be untenable. Experiments corroborating a central physical process of the paradox are discussed briefly. The paradox is discussed in the context of the Maxwell demon. (shrink)