It is noted that old belief in impossibility of any perpetuum mobile is the basis of the great confidence in the second law of thermodynamics. The Carnot’s principle, «called with the time of Rudolf Clausius as the second law of thermodynamics», was based on this belief and this belief saved the second law in the beginning of 20 century when absolute randomness of any Brownian motion, perpetual motion experimentally observed, was postulated. It is shown that this postulate is not correct according to quantum mechanics. Moreover experimental evidence of its violation is known. Violation of this postulate means violation of the second law and a possibility of useful perpetuum mobile.
It is noted that old belief in impossibility of any perpetuum mobile is the basis of the great confidence in the second law of thermodynamics. The Carnot’s principle, «called with the time of Rudolf Clausius as the second law of thermodynamics», was based on this belief and this belief saved the second law in the beginning of 20 century when absolute randomness of any Brownian motion, perpetual motion experimentally observed, was postulated. It is shown that this postulate is not correct according to quantum mechanics. Moreover experimental evidence of its violation is known. Violation of this postulate means violation of the second law and a possibility of useful perpetuum mobile.
One of the oldest science problems - possibility of the perpetuum mobile is discussed. The interest to this problem was provoke a result, published in J. Low Temp.Phys. 112, 227 (1998); cond-mat/9811148, which contradicts to the second law of thermodynamics. According to this result, the thermal fluctuations can induce a voltage with direct component in a inhomogeneous superconducting ring at an unaltered temperature corresponded to the resistive transition of the ring segment with the lowest critical temperature. This result arises from obvious statements: 1) the of a ring segment lb into and out of the normal state, while the rest of the ring (segment la) remains superconducting, can induced a voltage with dc component (It is shown that, in spite of the wide spread opinion, this statement is correct because the superconductivity is a macroscopic quantum phenomena); 2) the thermal fluctuations switch the mesoscopic ring segment lb with lowest critical temperature Tsb into and out of the normal state at T≃Tsb, while the rest of the ring remains superconducting if Tsa>T≃Tsb. In order to resolve the contradiction between these obvious statements and the second law of thermodynamics a possibility of the second order perpetuum mobile is considered theoretically. It is shown that from two type of the perpetuum mobile, only type b and only in quantum systems is possible. According to the presented interpretation, the total entropy, as the measure of the chaos, may be systematically reduced in some quantum system because a switching between the classical and quantum mechanics is possible. Instruction for the making of the perpetuum mobile is enclosed.
One of the oldest science problems - possibility of the perpetuum mobile is discussed. The interest to this problem was provoke a result, published in J. Low Temp.Phys. 112, 227 (1998); cond-mat/9811148, which contradicts to the second law of thermodynamics. According to this result, the thermal fluctuations can induce a voltage with direct component in a inhomogeneous superconducting ring at an unaltered temperature corresponded to the resistive transition of the ring segment with the lowest critical temperature. This result arises from obvious statements: 1) the switching of a ring segment lb into and out of the normal state, while the rest of the ring (segment la) remains superconducting, can induced a voltage with dc component (It is shown that, in spite of the wide spread opinion, this statement is correct because the superconductivity is a macroscopic quantum phenomena); 2) the thermal fluctuations switch the mesoscopic ring segment lb with lowest critical temperature Tsb into and out of the normal state at T≃Tsb, while the rest of the ring remains superconducting if Tsa>T≃Tsb. In order to resolve the contradiction between these obvious statements and the second law of thermodynamics a possibility of the second order perpetuum mobile is considered theoretically. It is shown that from two type of the perpetuum mobile, only type "b" and only in quantum systems is possible. According to the presented interpretation, the total entropy, as the measure of the chaos, may be systematically reduced in some quantum system because a "switching" between the classical and quantum mechanics is possible. Instruction for the making of the perpetuum mobile is enclosed.
The Brownian motion of a quantum particle in a harmonic confining potential and coupled to harmonic quantum thermal bath is exactly solvable. Though this system presents at high temperatures a pedagogic example to explain the laws of thermodynamics, it is shown that at low enough temperatures the stationary state is non-Gibbsian due to an entanglement with the bath. In physical terms, this happens when the cloud of bath modes around the particle starts to play a nontrivial role, namely, when the bath temperature T is smaller than the coupling energy. Indeed, equilibrium thermodynamics of the total system, particle plus bath, does not imply standard equilibrium thermodynamics for the particle itself at low T. Various formulations of the second law are found to be invalid at low T. First, the Clausius inequality can be violated, because heat can be extracted from the zero point energy of the cloud of bath modes. Second, when the width of the confining potential is suddenly changed, there occurs a relaxation to equilibrium during which the entropy production is partly negative. In this process the energy put on the particle does not relax monotonically, but oscillates between particle and bath, even in the limit of strong damping. Third, for nonadiabatic changes of system parameters the rate of energy dissipation can be negative, and, out of equilibrium, cyclic processes are possible which extract work from the bath. Conditions are put forward under which perpetuum mobility of the second kind, having one or several work extraction cycles, enter the realm of condensed matter physics. Fourth, it follows that the equivalence between different formulations of the second law (e.g., those by Clausius and Thomson) can be violated at low temperatures. These effects are the consequence of quantum entanglement in the presence of the slightly off-equilibrium nature of the thermal bath, and become important when the characteristic quantum time scale variant Planck's over 2pi /k(B)T is larger than or comparable to other time scales of the system. They show that there is no general consensus between standard thermodynamics and quantum mechanics. The known agreements occur only due to the weak coupling limit, which does not pertain to low temperatures. Experimental setups for testing the effects are discussed.
The Brownian motion of a quantum particle in a harmonic confining potential and coupled to a harmonic quantum thermal bath is exactly solvable. It is shown that at low enough temperatures the stationary state is non-Gibbsian due to an entanglement with the bath. In physical terms, this happens when the cloud of bath modes around the particle starts to play a non-trivial role. Indeed, equilibrium thermodynamics of the total system, particle plus bath, does not imply standard equilibrium thermodynamics for the particle itself at low T. Various formulations of the second law are found to be invalid at low T. First, the Clausius inequality can be violated, because heat can be extracted from the zero point energy of the cloud of bath modes. Second, when the width of the confining potential is suddenly changed, there occurs a relaxation to equilibrium during which the entropy production is partly negative. Third, for non-adiabatic changes of system parameters the rate of energy dissipation can be negative, and, out of equilibrium, cyclic processes are possible which extract work from the bath. Conditions are put forward under which perpetuum mobile of the second kind, having one or several work extraction cycles, enter the realm of condensed matter physics. Fourth, it follows that the equivalence between different formulations of the second law (e.g. those by Clausius and Thomson) can be violated at low temperatures. These effects are the consequence of quantum entanglement in the presence of the slightly off-equilibrium nature of the thermal bath, and become important when the characteristic quantum time scale ℏ/kBT is larger than or comparable to other timescale of the system. They show that there is no general consensus between standard thermodynamics and quantum mechanics.
The problem of possible violation of the second law of thermodynamics is discussed. It is noted that the task of the well known challenge to the second law called Maxwell's demon is put in order a chaotic perpetual motion and if any ordered Brownian motion exists then the second law can be broken without this hypothetical intelligent entity. The postulate of absolute randomness of any Brownian motion saved the second law in the beginning of the 20th century when it was realized as perpetual motion. This postulate can be proven in the limits of classical mechanics but is not correct according to quantum mechanics. Moreover some enough known quantum phenomena, such as the persistent current at non-zero resistance, are an experimental evidence of the non-chaotic Brownian motion with non-zero average velocity. An experimental observation of a dc quantum power soruce is interperted as evidence of violation of the second law.
It is argued using a Gedankenexperiment that a scalable quantum memory could be used as a perpetuum mobile of the second kind and hence cannot be realized in nature. The reasoning is based on the assumption that the Landauer's principle for measurements is a consequence of the second law of thermodynamics and not an independent postulate. This implies a modification of the Landauer's principle when applied for discrimination of equilibrium (metastable) states. While identification of the metastable state can be done at infinitesimally low cost, any change of such state involves dissipation of energy proportional to its stability factor.