Influence of gravity on a granular Maxwell’s demon experiment

Isert, Nathan; Maaß, Corinna C.; Aegerter, Christof M.

doi:10.1140/epje/i2008-10403-7

Cited by 9 publications

(10 citation statements)

References 11 publications

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“…On the other hand, the contact dynamics is deeply modified by such a method. More recently, the diamagnetism property of bismuth beads has been used to tune the apparent gravity [10]. In this paper, in order to test a gravity g lower than the Earth's gravity g, two experimental strategies have been approached (Fig.…”

Section: Introductionmentioning

confidence: 99%

Influence of a reduced gravity on the volume fraction of a monolayer of spherical grains

et al. 2011

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Centrifuge force is used to study granular materials in low gravity conditions. We consider a monolayer of noncohesive spherical grains placed on a plate. Reduced gravity conditions can be simulated in the plane by tilting or by rotating the plate. We compare both approaches experimentally. The volume fraction is found to increase with the apparent gravity and saturates. A model based on the exponential distribution of the Voronoi cell areas has been built and is in excellent agreement with the experimental data by extrapolating the fits of the data. Moreover, numerical simulations exhibit that more arches can be maintained at low apparent gravities than at high.

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Section: Introductionmentioning

confidence: 99%

Influence of a reduced gravity on the volume fraction of a monolayer of spherical grains

et al. 2011

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“…In that paper, it showed that a spontaneous symmetry breaking is possible in the absence of external fields. A recent work by Isert et al [21] used the properties of diamagnetic particles in strong magnetic field gradients to reduce and even balance the gravitation. A similar symmetry breaking has also been observed in their experiment.…”

Section: Discussionmentioning

confidence: 99%

Imperfect pitchfork bifurcation in asymmetric two-compartment granular gas

Yin

et al. 2013

Chinese Phys. B

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The clustering behavior of a mono-disperse granular gas is experimentally studied in an asymmetric two-compartment setup. Unlike the random clustering in either compartment in the case of symmetric configuration when lowering the shaking strength to below a critical value, the directed clustering is observed, which corresponds to an imperfect pitchfork bifurcation. Numerical solutions of the flux equation using a modified simple flux function show qualitative agreements with the experimental results. The potential application of this asymmetric structure is discussed.

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“…The MA has been proposed as a mechanism in the vortex tube [9], though this too is not a perpetual motion effect, and there are other ways to explain that specific phenomenon. Other interesting applications of MA principles are in phase separation of grains in microgravity or vibrational suspension [10], and it has been proposed that the inelasticity of collisions causes clustering [11]. Molecular Brownian ratchets have also been proposed [12].…”

Section: Empirical Applicationsmentioning

confidence: 99%

Entropy at the Level of Individual Particles: Analysis of Maxwell’s Agent with a Hidden-Variable Theory

Pons¹,

Pons²,

Pons³

2016

JMP

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Problem: Maxwell's Agent (MA) is a thought experiment about whether the second Law is violated at smaller scales. This is a complex problem because the scale dependencies are unclear for perfect gas assumptions, quantum coherence, thermalisation, and contextual measurement. Purpose: The MA is explored from a non-local hidden-variable (NLHV) perspective. Approach: The Cordus theory, a specific NLHV solution, was applied at macroscopic to fundamental scales. Physical realism requires the Agent be included in the analysis. Findings: The primary function is sorting, i.e. a one-time separation of species by some attribute. The thermodynamic MA situation is merely a special case for reducing disorder (entropy). A one-time extraction of energy is possible. This requires input energy, hence the device only has thermodynamic leverage and is not a perpetual motion device. Inefficiencies arise from thermalisation causing short mean free path of Brownian motion, perfect gases having minimal interaction with the gate, ambiguity about spatial location arising from quantum superposition, contextual measurement interfering with the particle velocity, and bremsstrahlung hysteresis losses occurring when the Agent operates. Implications: Entropy is a group property at the bulk level, not a characteristic of the individual particle, and can be reversed at an energy cost at the particle level. Originality: The explanation spans multiple levels from macroscopic down to fundamental, which is unusual. Achieving an explanation from the NLHV sector is novel. The theory accommodates superposition, irreversibility, entropy, contextual measurement, coherence-discord transition, and Brownian motion.

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Influence of gravity on a granular Maxwell’s demon experiment

Cited by 9 publications

References 11 publications

Influence of a reduced gravity on the volume fraction of a monolayer of spherical grains

Influence of a reduced gravity on the volume fraction of a monolayer of spherical grains

Imperfect pitchfork bifurcation in asymmetric two-compartment granular gas

Entropy at the Level of Individual Particles: Analysis of Maxwell’s Agent with a Hidden-Variable Theory

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