tag:blogger.com,1999:blog-3904639295706642486.post2636266437670087839..comments2023-10-21T08:48:37.363-07:00Comments on Zone-Reflex: Stochastic resonance.Unknownnoreply@blogger.comBlogger6125tag:blogger.com,1999:blog-3904639295706642486.post-74411411752511235482012-04-23T10:57:28.359-07:002012-04-23T10:57:28.359-07:00Geometric Stochastic Resonance
Pulak Kumar Ghosh,e...Geometric Stochastic Resonance<br />Pulak Kumar Ghosh,et-al, 2010 http://dml.riken.jp/pub/nori/pdf/PRL_104_020601_2010.pdf<br />A Brownian particle moving across a porous membrane subject to an oscillating force exhibits stochastic resonance with properties which strongly depend on the geometry of the confining cavities on the two sides of the membrane. Such a manifestation of stochastic resonance requires neither energetic nor entropic barriers, and can thus be regarded as a purely geometric effect. The magnitude of this effect is sensitive to the geometry of both the cavities and the pores, thus leading to distinctive optimal synchronization conditions.<br /><br />... particles are often confined to constrained geometries, such as interstices, pores, or channels, whose size and shape can affect the SR mechanism [4]. Indeed, smooth confining geometries can be modeled as entropic (i.e., noise or temperature dependent) potentials [5], capable of influencing the response of the system to an external driving force [6].Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-3904639295706642486.post-13207988513680063892012-04-23T10:42:12.941-07:002012-04-23T10:42:12.941-07:00Entropic stochastic resonance: the constructive ro...Entropic stochastic resonance: the constructive role of the unevenness<br />P.S. Burada, G. Schmid,a, D. Reguera, J.M. Rubi, and P. H¨anggi 2008. <br />http://www.physik.uni-augsburg.de/theo1/hanggi/Papers/529.pdf<br /><br />We demonstrate the existence of stochastic resonance (SR) in confined systems arising from entropy variations associated to the presence of irregular boundaries. When the motion of a Brownian particle is constrained to a region with uneven boundaries, the presence of a periodic input may give rise to a peak in the spectral amplification factor and therefore to the appearance of the SR phenomenon. We have proved that the amplification factor depends on the shape of the region through which the particle moves and that by adjusting its characteristic geometric parameters one may optimize the response of the system. The situation in which the appearance of such entropic stochastic resonance (ESR) occurs is common for small-scale systems in which confinement and noise play an prominent role. The novel mechanism found could thus constitute an important tool for the characterization of these systems and can put to use for controlling their basic properties.<br /><br />Up to now, the phenomenon of SR has been observed mainly in systems dominated by the presence of a purely energetic potential or possessing some dynamical threshold [1]. However, when scaling down the size of a system, the free energy rather than the internal energy becomes the most appropriate potential, and there are cases in which changes in the free energy are mainly due to entropy variations [11,13–18]. This is what occurs in constrained systems. In the case of a Brownian particle moving in a confined medium, entropy variations contribute to changes in the free energy and may under some circumstances become its leading contribution [12,13,17,18].Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-3904639295706642486.post-36956287121400736132012-04-23T10:35:02.912-07:002012-04-23T10:35:02.912-07:00http://matpitka.blogspot.com/2012/04/higgs-and-fin...http://matpitka.blogspot.com/2012/04/higgs-and-finnish-folklore.html#c7561013130073256378<br /><br />I have discussed stochastic resonance in the model of EEG as a mechanism to generate "coctail party effect".<br /><br />I have concentrated mainly to topics which distinguish TGD from other theories: in particular from theories which could be called generic: catastrophe theory, chaos theory, stochastic resonance, etc.. Most of the model building during last four decades relies on the assumption that gauge theories are somehow generic: you such take standard model, select gauge group, select representations for particles, select symmetry breaking and calculate beta function. This is completely mechanized waste of time but has produced impressive number of thesis works and publications. Super string theories continue the noble tradition and with some additional recipes making able to move in landscape one ends up to similar procedure. All goes wrong already at the first step: proton is predicted to decay but there is not a single thread of evidence for this.<br /><br /><br />ZEO implies two kinds of symmetries.<b> The zero energy states themselves become the symmetry algebra of the zero energy states. Amusing self referentiality again. This symmetry is non-local in the sense that point like particles are replaced by partonic 2-surfaces and one has something analogous to conformal algebra. It is also multilocal with respect to the partonic 2-surfaces - even at the point-like liit - as is generalization of Yangian symmetry. ZEO implies that the products for Hermitian square roots of density matrices forming a basis multiplied by powers of S-matrix S defined the algebra and this algebra generalizes the Kac-Moody type algebra.</b><br /><br />This must be extremely powerful symmetry but I am unable to deduce its consequences.<br /><br />There is second symmetry. It is due to finite measurement resolution which one might call "thermodynamical". In the representation of finite measurement resolution as gauge invariance, one has complete gauge invariance so that these non-observable degrees of freedom are eliminated. In ordinary gauge invariance same holds true almost: almost because the gauge charges can be non-vanishing. For a complete gauge symmetry they would vanish. I remember that HB had talk about his idea of immensely large gauge symmetry which would break down to observed: I am not enthusiastic: proton stability kills the extension of gauge symmetry as a recipe to produce theories of everything.Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-3904639295706642486.post-48474865744189826132012-04-23T10:30:11.196-07:002012-04-23T10:30:11.196-07:00Quantum model for EEG, in TGD, http://tgdtheory.co...Quantum model for EEG, in TGD, http://tgdtheory.com/public_html/pdfpool/eegII.pdf<br /><br />Stochastic resonance is known to be relevant also at the neuronal level as demonstrated by the autocorrelation functions for spike sequences <b>exhibiting peaks at the harmonics of the signal frequency.</b> Neuron is however far from being bistable system, and this raises the question whether bi-stability might be present at some deeper quantal level.<br /><br />Nerve pulses generate EEG MEs and the frequency of the nerve pulses determines the rate at which EEG MEs are generated rather than the frequency of EEG MEs. TGD inspired model of nerve pulse assigns to the resting state of cell a propagating soliton sequence and nerve pulse corresponds to a perturbation which locally transformation propagation to oscillations. The states correspond to the states of the bistable system. The system in resting state is near criticality in the sense that rotation velocity is slightly above the minimum one so that reduction of membrane potential transforms rotation motion to oscillatory motion locally. Stochastic resonances makes itself visible in the autocorrelation function of the spike sequence and in this manner also in the membrane potential of say glial cells coupling to neurons. In fact, glial cells could play the role of listener of radio turning the knob (noise level) to tune the neurons to a particular spiking frequency.<br /><br />Stochastic resonance and brain at p. 19.<br />With motivations coming from conceptual difficulties of the proposed neuronal models, a reduction of the stochastic resonance to the quantum level, which is assumed to control the functioning of bio-systems, is developed by refi ning the quantum model for nerve pulse generation by specifying the interaction with MEs. Another key idea described in detail in [1] is that bio-systems correspond to flow equilibria for ions in the many-sheeted space-time with atomic space-time sheets having the role of a controlled system and super-conducting space-time sheets taking the role of the controlling system. The possibility that MEs generate by stochastic resonance soliton sequences associated with Josephson currents, is discussed p. 19 - 24.Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-3904639295706642486.post-63736309109209693772012-04-14T23:57:56.086-07:002012-04-14T23:57:56.086-07:00From Physics Forum threads:
Are there any relativi...From Physics Forum threads:<br />Are there any relativistic thermodynamics book around or perhaps a physics review of this subject?<br /><br />There is a section in Relativity, Thermodynamics and Cosmology, by Richard C. Tolman, Dover Pub, 2011 It starts on page 118 and ends on page 164.<br /><br />http://books.google.fi/books/about/Relativity_Thermodynamics_and_Cosmology.html?id=1ZOgD9qlWtsC&redir_esc=y<br /><br />relativistic vs non-relativistic momentum<br />If you wanted to be more precise you could find the ratio of classical to relativistic momentum. Or you could find the percentage difference between the two, e.g. "the relativistic momentum is 4.2% larger than the classical momentum."<br /><br /><br />Classical Physics states that:<br /><br />p=mv<br /><br />So, for special relativity, would momentum be defined in the same manner except m is now equal to the relativistic mass instead of the standard 'rest mass' as used in the classical equation?<br /><br />...to ensure there wasnt any of the Transformations that had to apply to the velocity or anything of that nature. I was pretty sure it was just the mass change....<br /><br /><br />My comment to this is, well,look at the measurement procedure and what happen with energy then! Are they sleeping?Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.comtag:blogger.com,1999:blog-3904639295706642486.post-70275707111213905542012-04-14T23:42:58.511-07:002012-04-14T23:42:58.511-07:00Relativistic thermodynamics
Sean A. Hayward
(Submi...Relativistic thermodynamics<br />Sean A. Hayward<br />(Submitted on 2 Mar 1998 (v1), last revised 29 Jan 1999 (this version, v2))<br /><br /> A generally relativistic theory of thermodynamics is developed, based on four main physical principles: heat is a local form of energy, therefore described by a thermal energy tensor; conservation of mass, equivalent to conservation of heat, or the local first law; entropy is a local current; and non-destruction of entropy, or the local second law. A fluid is defined by the thermostatic energy tensor being isotropic. The entropy current is related to the other fields by certain equations, including a generalised Gibbs equation for the thermostatic entropy, followed by linear and quadratic terms in the dissipative (thermal minus thermostatic) energy tensor. Then the second law suggests certain equations for the dissipative energy tensor, generalising the Israel- Stewart dissipative relations, which describe heat conduction and viscosity including relativistic effects and relaxation effects. In the thermostatic case, the perfect-fluid model is recovered. In the linear approximation for entropy, the Eckart theory is recovered. In the quadratic approximation for entropy, the theory is similar to that of Israel & Stewart, but involving neither state-space differentials, nor a non-equilibrium Gibbs equation, nor non-material frames. Also, unlike conventional thermodynamics, the thermal energy density is not assumed to be purely thermostatic, though this is derived in the linear approximation. Otherwise, the theory reduces in the non-relativistic limit to the extended thermodynamics of irreversible processes due to Mueller. <b>The dissipative energy density seems to be a new thermodynamical field,</b> but also exists in relativistic kinetic theory of gases. <br /><br />Comments: 26 pages, plain Tex, presentational changes<br />Subjects: General Relativity and Quantum Cosmology (gr-qc)<br />Cite as: arXiv:gr-qc/9803007v2Ullahttps://www.blogger.com/profile/16634036177244152897noreply@blogger.com