Theoretical predictions from Intrinsic Quantum Thermodynamics (IQT) are compared to published experimental findings in order to examine whether or not calculations using IQT are consistent with experimental data. IQT makes the assertion that entropy is an intrinsic property of matter in the same way that inertial mass, energy, and momentum are and must, thus, exist even for single particles. Entropy as defined by IQT is a measure of the distribution of a system's internal energy at any given instant of time amongst the available internal degrees of freedom, i.e., the energy eigenlevels of the system. In this paper, it is shown that IQT models the internal relaxation of a 5-level rubidium system in a way that is consistent with the experimental data available in the literature. In addition, other experimental data found in the literature is compared with results obtained from the equation of motion of IQT that allows for heat interactions. It is shown that the decay of so-called "cat states" for single ions that are contained in Paul traps and that interact with a heat reservoir is also consistent with the calculations made using the theory of IQT.
Theoretical predictions from Intrinsic Quantum Thermodynamics (IQT) are compared to published experimental findings in order to examine whether or not calculations using IQT are consistent with experimental data. IQT makes the assertion that entropy is an intrinsic property of matter in the same way that inertial mass, energy, and momentum are and must, thus, exist even for single particles. Entropy as defined by IQT is a measure of the distribution of a system's internal energy at any given instant of time amongst the available internal degrees of freedom, i.e., the energy eigenlevels of the system. In this paper, it is shown that IQT models the internal relaxation of a 5-level rubidium system in a way that is consistent with the experimental data available in the literature. In addition, other experimental data found in the literature is compared with results obtained from the equation of motion of IQT that allows for heat interactions. It is shown that the decay of so-called "cat states" for single ions that are contained in Paul traps and that interact with a heat reservoir is also consistent with the calculations made using the theory of IQT.
Experimental evidence is presented and compared with theoretical predictions from Quantum Thermodynamics, (QT) to examine whether or not the claims of QT are consistent with the existence and generation of entropy at atomistic scales. QT makes the assertion that entropy is an intrinsic property of matter in the same way that inertial mass, energy, and momentum are and must, thus, exist even for single particles. Entropy as defined by QT is a measure of the distribution of a system’s internal energy at any given instant of time amongst the available internal degrees of freedom, i.e., the energy eigenlevels of the system. In this paper, it is shown that QT predicts the internal relaxation of a 5-level rubidium system that is consistent with the experimental data and not explained by current theory, i.e. by Quantum Mechanics. In addition, it is demonstrated that the decay of so-called “cat states” for single ions that are contained in Paul traps and that interact with a heat reservoir is also consistent with the idea of the existence of entropy and entropy generation at atomistic scales. This is accomplished by comparing experimental data with the predictions made using an extension of the equation of motion of QT that allows for heat interactions.
Intrinsic Quantum Thermodynamics (IQT) is a theory that combines Thermodynamics and Quantum Mechanics into a single theory and asserts that irreversibility and the increase of entropy has its origin at the fundamental, atomistic level. The merits and details of IQT are discussed and compared with the well-known theory of Quantum Statistical Mechanics (QSM) and the more recent development of Quantum Thermodynamics (QT). IQT is then used to model in 3D the time evolution of the adsorption of hydrogen on a single-walled carbon nanotube. The initial state of the hydrogen molecules is far from stable equilibrium and over time the system relaxes to a state of stable equilibrium with the hydrogen near the walls of the carbon nanotube. The details of the model are presented, which include the construction of the energy eigenlevels for the system, the treatment of the interactions between the hydrogen and the nanotube along with the interactions of the hydrogen molecules with each other, and the solution of the IQT equation of motion as well as approximation methods that are developed to deal with extremely large numbers of energy eigenlevels. In addition, a new extension to the theory of IQT is proposed for modeling systems that undergo heat interactions with a heat reservoir. The formulation of a new heat interaction operator is discussed, implemented, tested, and compared with a previous version extant in the literature. IQT theory is then further extended to encompass simple mass interactions with a mass reservoir. The formulation, implementation, and testing of the mass interaction operator is also discussed in detail. Finally, IQT is used to model the results of two experiments found in the literature. The first experiment deals with the spin relaxation of rubidium atoms and the second tests the relaxation behavior of single trapped ion that is allowed to interact with an external heat reservoir. Good agreement between experiment and the model predictions is found.
Quantum thermodynamics (QT) provides a general framework for the description of non-equilibrium phenomena at any level, particularly the atomistic one. This theory and its dynamical postulate are used here to extend the work reported in previous papers of modeling the storage of hydrogen in an isolated system, by extending the modeling to 3D. The system is prepared in a state with the hydrogen molecules initially far from stable equilibrium after which the system is allowed to relax (evolve) to a state of stable equilibrium. The so-called energy eigenvalue problem, which entails a many-body problem that for dilute and moderately dense gases can be solved using virial expansion theory, is used to determine the energy eigenvalues and eigenstates of the system. This information is then used in the nonlinear Beretta equation of motion of QT to determine the evolution of the thermodynamic state of the system as well as the spatial distributions of the hydrogen molecules in time. The results of our simulations provide a quantification of the entropy generated due to irreversibilities at an atomistic level and show in detail the trajectory of the state of the system as the hydrogen molecules, which are initially arranged to be far from the carbon nanotube, spread out in the system and eventually become more concentrated near the carbon atoms which make up the nanotube
Quantum thermodynamics (QT) provides a general framework for the description of non-equilibrium phenomena at any level, particularly the atomistic one. This theory and its dynamical postulate are used here to model the storage of hydrogen on and in a carbon nanotube. The tube is placed at the center of a tank with a volume of 250 nm 3 . The thermodynamic system of interest is the hydrogen, which is assumed isolated and having boundaries that coincide with the walls of the tank and the carbon nanotube. The hydrogen is initially prepared in a state far from stable equilibrium (i.e., with the hydrogen molecules probabilistically near one of the outer tank walls) after which the system is allowed to relax (evolve) to a state of stable equilibrium. To predict this evolution in state, the so-called energy eigenvalue problem, which entails a many-body problem that for dilute and moderately dense gases can be modeled using virial expansion theory, is first solved for the geometry involved. The energy eigenvalues and eigenstates of the system found are then used by the nonlinear Beretta equation of motion of QT to determine the evolution of the thermodynamic state of the system as well as the 3D spatial distributions of the hydrogen molecules in time. The simulation results provide a quantification of the entropy generated due to irreversibilities at an atomistic level and show in detail the trajectory of the thermodynamic state of the system as the hydrogen molecules, which are initially arranged to be far from the carbon nanotube, spread out in the system and eventually become probabilistically more concentrated near the carbon atoms, which make up the nanotube.
In the scientific and engineering literature, entropy—the distinguishing feature of thermodynamics from other branches of physics—is viewed with skepticism, and thought to be not a physical property of matter—like mass or energy—but a measure either of disorder in a system, or of lack of information about the physics of a system in a thermodynamic equilibrium state, and a plethora of expressions are proposed for its analytical representation. In this article, I present briefly two revolutionary nonstatistical expositions of thermodynamics (revolutionary in the sense of Thomas Kuhn, The Structure of Scientific Revolutions, U. Chicago Press, 1970) that apply to all systems (both macroscopic and microscopic, including one spin or a single particle), to all states (thermodynamic equilibrium, and not thermodynamic equilibrium), and that disclose entropy as an intrinsic property of matter.The first theory is presented without reference to quantum mechanics even though quantum theoretic ideas are lurking behind the exposition. The second theory is a unified quantum theory of mechanics and thermodynamics without statistical probabilities, that is, I am not presenting another version of statistical quantum mechanics.
An explicit expression for the temperature of an open two-level quantum system is obtained as a function of local properties under the hypothesis of weak interaction with the environment. This temperature is defined for both equilibrium and out-of-equilibrium states and coincides with the environment temperature if the system reaches thermal equilibrium with a heat reservoir. Additionally, we show that within this theoretical framework the total entropy production can be partitioned into two contributions: one due to heat transfer and another, associated to internal irreversibilities, related to the loss of internal coherence by the qubit. The positiveness of the heat capacity is established, as well as its consistency with the well-known results at thermal equilibrium. We apply these concepts to two different systems and show that they behave in analogous ways as their classical counterparts.