SECOND LAW OF THERMODYNAMICS: STATUS AND CHALLENGES
1411(2011); http://dx.doi.org/10.1063/1.3665227View Description Hide Description
1411(2011); http://dx.doi.org/10.1063/1.3665228View Description Hide Description
Through hard‐disk simulations and theoretical considerations on the movement of an object that partitions a microtubule filled with small particles, we find that the vibrations typical of thermal equilibrium are reached after a time that increases exponentially with the number of particles involved. The result is a mechanism capable of breaching, on accessible time scales, the ergodic constraints in nano‐scale systems.
1411(2011); http://dx.doi.org/10.1063/1.3665229View Description Hide Description
A system's entropy is maximized not when it is localized in its most probable macrostate, but when it is in its most probable distribution of macrostates. This distribution includes all macrostates, including, albeit typically with much smaller probability than the most probable macrostate, those far removed from the most probable one. It is this distribution, and not the most probable macrostate alone, that characterizes true ther‐modynamic equilibrium. Thus, work, albeit typically only in small amounts, is extractable from a system localized in its most probable macrostate. We demonstrate these points via a simple system. We show that a small amount of work can be extracted from a box of gas in thermal equilibrium with a heat reservoir even if the gas is in its most probable macrostate with exactly half of the gas molecules in both the left and right halves of the box. We then qualitatively consider the relation to the adiabatic piston problem.
1411(2011); http://dx.doi.org/10.1063/1.3665230View Description Hide Description
argued that a ratchet of the type used in heavy machinery could be used, in a scaled‐down version, to show that the second law of thermodynamics is not just a statistical law, but has absolute status. Hidden is the assumption that this model represented the completely general example of this device—and that it remained so, across the complete range of magnitudes from macro‐ to micro‐domains. It will be argued here, that Feynman's example is only one construct of a ratchet and cannot represent the general case. A mechanism, with sufficient difference and confined to the micro‐domain, is the subject of the present discussion. Its unique feature is the compressible nature of the pawl as it librates in pawl‐space. The motions of the gear and the pawl are governed by the energy exchanges between them and with the ambient gas. The average linear pressure on the pawl which varies with the magnitude of pawl‐space is associated with the compressibility of the pawl.
Feynman's objective was to show that the prototypal ratchet is incapable of converting heat into work in a manner contrary to the second law. The dubious nature of his examination is not due to an incorrect analysis of his thought experiment, but lies within the assumption that his example represented the general case. In contrast, the ratchet analyzed here does not conform to the principle of detailed balance and thereby the absolute status of the law remains an open question.
1411(2011); http://dx.doi.org/10.1063/1.3665231View Description Hide Description
Some foundational considerations on the peculiar status of the second law as a law of physics are made. Given the atomic nature of matter, whose behaviour is well described by statistical physics, the second law could not hold unconditionally, but only statistically. It is not an absolute law. We argue that this peculiar condition is the main rationale and motivation for pursuing exploratory research to challenge the second law.
Recently [D'Abramo, Phys. Lett. A 374 (2010) 1801, and D'Abramo, Physica A 390/3 (2011) 482] the concept of vacuum capacitor spontaneously charged harnessing the heat from a single thermal reservoir at room temperature has been introduced, along with a mathematical description of its functioning and a discussion on the main paradoxical feature that seems to violate the second law of thermodynamics.
Here we briefly review these works. We describe the theoretical and practical possibility of exploiting such a thermo‐charged capacitor as voltage/current generator: if very weak provisos on the physical characteristics of the capacitor are fulfilled, then a non‐zero current should flow across the device, allowing the generation of potentially usable voltage, current and electric power out of a single thermal source at room temperature. Preliminary results show that the power output is tiny but non‐zero.
Experimental Challenge to the Second Law of Thermodynamics in High‐Temperature, Gas‐Surface Reactions1411(2011); http://dx.doi.org/10.1063/1.3665232View Description Hide Description
It has been proposed that differences in the adsorption, desorption, dissociation, and recombination rates of chemical species between surfaces can give rise to steady‐state pressure and temperature gradients within a single blackbody cavity under low‐pressure conditions [1‐5]. Such gradients would implicitly violate the second law of thermodynamics. This paper reports on laboratory tests of this proposal. Low‐pressure molecular hydrogen was found to dissociate and desorb preferentially on rhenium compared with tungsten at elevated temperatures Blackbody cavities are being constructed from these metals, and their interior surface temperatures monitored. Steady‐state temperature gradients, due to differential gas‐surface reactions, would signal second law breakdown.
Transformation of Thermal Energy into Electric Energy via Thermionic Emission of Electrons from Dielectric Surfaces in Magnetic Fields1411(2011); http://dx.doi.org/10.1063/1.3665233View Description Hide Description
It is shown that electrostatic potentials can be created under equilibrium conditions by the Lorentz force motion of thermionic electrons over dielectric surfaces, setting the stage for a conflict with the second law of thermodynamics. These predicted electrostatic potentials have been demonstrated experimentally. We advance this phenomenon as evidence for the feasibility of direct conversion of thermal energy into electricity in the absence of a temperature difference. This challenge to the second law of thermodynamics is compared with related ones.
1411(2011); http://dx.doi.org/10.1063/1.3665234View Description Hide Description
A heat engine is presented in which the working media comprises a multiplicity of mutually isolated particles of Type I superconductor which are selectively processed through H‐T phase space so as to convert a heat influx from a high temperature heat reservoir into a useful work output, wherein no heat is rejected to a low temperature heat reservoir.
Observations of Persistent Current at Non‐Zero Resistance: Challenge to the Second Law of Thermodynamics1411(2011); http://dx.doi.org/10.1063/1.3665235View Description Hide Description
This article details why the mesoscopic quantum phenomenon known as persistent current challenges the second law of thermodynamics. The persistent current is an equilibrium phenomenon as real as Nyquist (Johnson) noise, but in contrast, it is not random; its direct component (i.e. zero‐frequency component) is non‐zero because of the discreteness of the permitted state spectrum of electrons in normal metal rings and Cooper pairs in superconductor rings. The persistent current observed in mesoscopic rings with non‐zero resistance is effectively directed Brownian motion, which cannot decay despite its non‐zero energy dissipation. This is due to the equilibration between the dissipative force with the change of angular momentum of electrons (or Cooper pairs), owing to the quantization condition on the wave function describing their states in the ring. The observations of electric potential difference on ring‐halves having persistent current raise the possibility of utilizing persistent currents for useful work, in conflict with the second law.
1411(2011); http://dx.doi.org/10.1063/1.3665236View Description Hide Description
Over the last ten years, researchers at USD have investigated a series of challenges to the second law of thermodynamics that involve the exploitation of intense vacuum electric fields generated by solid‐state diodic contacts [1, 2, 3]. Although theoretical arguments and numerical simulations supported the existence of these fields, experimental verification had been lacking. This article reviews the theoretical basis for these diodic electric fields and details recent laboratory experiments that have verified their location, intensity, and rechargability.
1411(2011); http://dx.doi.org/10.1063/1.3665237View Description Hide Description
There have been a number of experimental results that show that the magnetomechanical coupling in certain magnetostrictive materials do not satisfy the thermodynamic Maxwell relations. These startling results have come from different laboratories including the Naval Surface Warfare Center, Carderock Division and the University of Maryland, College Park. If these experiments are correct, and the Maxwell relations are violated, the experiments represent the very important discovery of magnetic materials that do obey the standard thermodynamic laws.
In this paper, the experimental evidence will be presented along with the theoretical analysis demonstrating that the experimental data is not consistent with the existence of the standard thermodynamic potentials, and demonstrating how magnetomechanical cycles may be constructed by which energy can be extracted from the ambient temperature environment. Experimental measurements of an extraction of energy in such magnetomechanical cycles will also be presented.
1411(2011); http://dx.doi.org/10.1063/1.3665238View Description Hide Description
Maxwell's Demon is a legitimate challenge to the Second Law of Thermodynamics when the “demon” is executed via the Proell effect. Thermal energy transfer according to the Kinetic Theory of Heat and Statistical Mechanics that takes place over distances greater than the mean free path of a gas circumvents the microscopic randomness that leads to macroscopic irreversibility. No information is required to sort the particles as no sorting occurs; the entire volume of gas undergoes the same transition. The Proell effect achieves quasi‐spontaneous thermal separation without sorting by the perturbation of a heterogeneous constant volume system with displacement and regeneration. The classical analysis of the constant volume process, such as found in the Stirling Cycle, is incomplete and therefore incorrect. There are extra energy flows that classical thermo does not recognize. When a working fluid is displaced across a regenerator with a temperature gradient in a constant volume system, complimentary compression and expansion work takes place that transfers energy between the regenerator and the bulk gas volumes of the hot and cold sides of the constant volume system. Heat capacity at constant pressure applies instead of heat capacity at constant volume. The resultant increase in calculated, recyclable energy allows the Carnot Limit to be exceeded in certain cycles. Super‐Carnot heat engines and heat pumps have been designed and a US patent has been awarded.
1411(2011); http://dx.doi.org/10.1063/1.3665239View Description Hide Description
In order to clarify the dispute between Loschmidt and Boltzmann/Maxwell concerning the existence of a temperature gradient in insulated vertical columns of gas, liquid or solids, macroscopic measurements of the temperature distribution in air, water and solids were performed. A negative temperature gradient, cold at the top and warm at the bottom, is found in insulated vertical tubes, while the outside environment has a reverse gradient. This is explainable by the influence of gravity. It allows the production of electricity out of a heat bath.
1411(2011); http://dx.doi.org/10.1063/1.3665240View Description Hide Description
When a charge accelerates, its field‐lines curve in a typical pattern. This pattern resembles the curvature induced on the field‐lines by a neighboring charge. Not only does the latter case involve a similar curvature, it moreover results in attraction/repulsion. This suggests a hitherto unnoticed causal symmetry: charge acceleration ⇔ field curvature. We prove quantitatively that these two phenomena are essentially one and the same. The field stores some of the charge's mass, yet it is extended in space, hence when the charge accelerates, inertia makes the field lag behind. The resulting stress in the field stores some of the charge's kinetic energy in the form of potential energy. The electrostatic interaction is the approximate mirror image of this process: The potential energy stored within the field turns into the charge's kinetic energy. This partial symmetry offers novel insights into two debated issues in electromagnetism The question whether a charge radiates in a gravitational field receives a new twist: If all the charge's field‐lines end with opposite charges that also resist gravity, no radiation is expected. Similarly for the famous absence of a physical manifestation of the Maxwell equations′ advanced solution: Just as Einstein argued, the reason for this absence is probabilistic rather than reflecting some inherent time‐asymmetry. Despite the apparent equivalence between the “ontological” and “instrumentalist” viewpoints concerning the physical reality of field‐lines, there may be cases in which their experimental predictions differ.
1411(2011); http://dx.doi.org/10.1063/1.3665241View Description Hide Description
The phenomenon suggested by the title should surprise no one. What may be surprising is how easy it is to produce a quantum system with this feature; moreover, that system is one that is often used for showing how systems equilibrate. We provide an example where two systems can be brought into repeated contact, not be at the same temperature, but nevertheless no energy passes between them, nor is any work needed maintain disequilibrium.
1411(2011); http://dx.doi.org/10.1063/1.3665242View Description Hide Description
Quantum coherence can increase the quantum efficiency of various thermodynamic systems. For example, we can enhance the quantum efficiency for a quantum dot photocell, a laser based solar cell and the photo‐Carnot quantum heat engine. Our results are fully consistent with the laws of thermodynamics contrary to comments found in the paper of A. P. Kirk, Phys. Rev. Lett. 106, 048703 (2011).
1411(2011); http://dx.doi.org/10.1063/1.3665243View Description Hide Description
There is a body of conventional wisdom that holds that a solvable quantum problem, by virtue of its solvability, is pathological and thus irrelevant. It has been difficult to refute this view owing to the paucity of theoretical constructs and experimental results. Recent experiments involving equivalent ions trapped in a spatial conformation of extreme anisotropic confinement (longitudinal extension tens, hundreds or even thousands of times transverse extension) have modified the view of relevancy, and it is now possible to consider systems previously thought pathological, in particular point Bosons that repel in one dimension. It has been difficult for the experimentalists to utilize existing theory, mainly due to long‐standing theoretical misunderstanding of the relevance of the permutation group, in particular the non‐commutativity of translations (periodicity) and transpositions (permutation). This misunderstanding is most easily rectified in the case of repelling Bosons.
1411(2011); http://dx.doi.org/10.1063/1.3665244View Description Hide Description
To the student of thermodynamics the most difficult subject is entropy. In this paper we examine the actual, practical application of entropy to two simple systems, the homogeneous slab with fixed boundary values of the temperature, and an isolated atmosphere in the presence of the static gravitational field. The first gives valuable insight into the nature of entropy that is subsequently applied to the second system. It is a basic tenet of thermodynamics that the equilibrium of an extended, homogeneous and isolated system is characterized by a uniform temperature distribution and it is a strongly held belief that this remains true in the presence of gravity. We find that this is consistent with the equations of extended thermodynamics but that entropy enters in an essential way. The principle of equivalence takes on a new aspect.
1411(2011); http://dx.doi.org/10.1063/1.3665245View Description Hide Description
Time reversibility concepts and transformations are first reviewed and difficulties with the standard formulations indicated. The kinetic equations which were constructed to exhibit reciprocity relations in their transition probabilities based on time reversal ideas are examined next and a first principle analysis shows that the standard forms are not in accord with the first principles. A thermodynamical theory based on the Kelvin‐Clausius‐Planck definition of entropy and a modified form of the Benofy and Quay postulate concerning conductive heat is developed and reciprocity and other relations are derived as an example of one possible alternative to the standard treatments with their indicated inconsistencies.