arXiv subjects

François Fillaux

Publications and source records attributed to François Fillaux.

10 recordsLinked to original sources

arXiv2024

Description of the condensed phases of water in terms of Bose-Einstein condensates

I show that the reason why many properties of water are notoriously at odds with current models is the low dissociation energy of the H-bond, which leads to the instability of the Maxwell-Boltzmann distribution. Bose-Einstein condensation at the gas-liquid transition stabilizes the H-bond and opens the door to a reasoning from the laws of quantum mechanics to classical physics, explaining the properties of the condensed phases with only four observables and no arbitrary hypotheses. The isomorphic structures are composed of honeycomb sheets. Heat transfer reveals the eigenstates that determine the temperatures of the phase transitions. Quantum entanglement and degeneracy explain the heat capacities and latent heats. The supercooled liquid is a superposition of the high and low density eigenstates. Bose-Einstein condensation also explains the honeycomb pattern of an aerosol of droplets.

cond-mat.stat-mech↗

arXiv2021

A unified quantum-classical theory of the thermal properties of ice, liquid water and steam

The thermal properties of ice, liquid water and steam are at odds with statistical theories applied to many-body systems. Here, these properties are quantitatively explained with a bulk-scale matter field emerging from the indefinite status of the microscopic constituents. Such a field is characterized by its symmetry in spacetime, its degree of degeneracy and its eigenstates. There are several one-to-one correspondences bridging outcomes of classical and quantum measurements. (i) The heat capacities are linked to the symmetry of the field for each phase of water. (ii) The latent heats are linked to the change of the degree of degeneracy for each transition. (iii) The critical temperatures are linked to the eigenstates of the potential operator. The matter field leads to a complete representation of the phases of water, free of hidden parameters and statistical ignorance

cond-mat.stat-mech↗

arXiv2019

Quantum crystals are at odds with the laws of thermodynamics

Experimental data and the principles of quantum mechanics suggest that a crystal is a condensate of `wavicles' enclosed in a box, where `wavicle' denotes the indefinite wave-particle status of the microscopic constituents. When it is not perturbed the crystal is in a classical-like state. The wavefunction, the internal energy and the entropy are all of them equal to zero. The thermodynamic temperature is indefinite. Perturbations via energy- and/or momentum-transfer reveal quantum effects. The temperature laws for the heat capacities of some hydrogen-bonded crystals are rationalized with superposition states depending on the quantum temperature which is crystal-dependent. Heat-transfer is a coherent anentropic process. Apart from energy conservation, the other laws of thermodynamics are irrelevant.

quant-ph↗

arXiv2012

Neutron scattering studies of K$_3$H(SO$_4)_2$ and K$_3$D(SO$_4)_2$: The particle-in-a-box model for the quantum phase transition

In the crystal of K$_3$H(SO$_4)_2$, or K$_3$D(SO$_4)_2$, dimers (SO$_4)...$H$...$(SO$_4)$, or (SO$_4)...$D$...$(SO$_4)$, are linked by strong centrosymmetric hydrogen or deuterium bonds whose O$...$O length is $\approx 2.50$ Å. We address two open questions. (i) Are H or D sites split or not? (ii) Is there any structural counterpart to the phase transition observed for K$_3$D(SO$_4)_2$ at $T_c \approx 85.5$ K, that does not exist for K$_3$H(SO$_4)_2$. Neutron diffraction by single-crystals at cryogenic or room temperature reveals no structural transition and no resolvable splitting of H or D sites. However, the width of the probability densities suggest unresolved splitting of the wavefunctions suggesting rigid entities H$_{L1/2}-$H$_{R1/2}$ or D$_{L1/2}-$D$_{R1/2}$ whose separation lengths are $l_\mathrm{H} \approx 0.16$ Å\ or $l_\mathrm{D} \approx 0.25$ Å. The vibrational eigenstates for the center of mass of H$_{L1/2}-$H$_{R1/2}$ revealed by inelastic neutron scattering are amenable to a square-well and we suppose the same potential holds for D$_{L1/2}-$D$_{R1/2}$. In order to explain dielectric and calorimetric measurements of mixed crystals K$_3$D$_{(1-ρ)}$H$_ρ$(SO$_4)_2$ ($0 \le ρ\le 1$), we replace the classical notion of order-disorder by the quantum notion of discernible (eg D$_{L1/2}-$D$_{R1/2}$) or indiscernible (eg H$_{L1/2}-$H$_{R1/2}$) components depending on the separation length of the split wavefunction. The discernible-indiscernible isostructural transition at finite temperatures is induced by a thermal pure quantum state or at 0 K by $ρ$.

cond-mat.other↗

arXiv2011

A neutron diffraction study from 6 to 293 K and a macroscopic-scale quantum theory of the hydrogen bonded dimers in the crystal of benzoic acid

The crystal of benzoic acid is comprised of tautomeric centrosymmetric dimers linked through bistable hydrogen bonds. Statistical disorder of the bonding protons is excluded by neutron diffraction from 6 K to 293 K. In addition to diffraction data, vibrational spectra and relaxation rates measured with solid-state-NMR and quasi-elastic neutron scattering are consistent with wave-like, rather than particle-like protons. We present a macroscopic-scale quantum theory for the bonding protons represented by a periodic lattice of fermions. The adiabatic separation, the exclusion principle, and the antisymmetry postulate yield a static lattice-state immune to decoherence. According to the theory of quantum measurements, vibrational spectroscopy and relaxometry involve realizations of decoherence-free Bloch states for nonlocal symmetry species that did not exist before the measurement. The eigen states are fully determined by three temperature-independent parameters which are effectively measured: the energy difference between tautomer sublattices; the double-well asymmetry for proton oscillators; the delocalization degree of the wavefunctions. The spontaneous decay of Bloch states accounts for relaxometry data. On the other hand, static states realized by elastic scattering account for diffraction data. We conclude that both quantum and classical physics hold at every temperature.

physics.chem-ph↗

arXiv2010

Evidence of macroscopically entangled protons in a mixed isotope crystal of KH$_{p}$D$_{1-p}$CO$_3$

We examine whether protons and deuterons in the crystal of KH$_{0.76}$D$_{0.24}$CO$_3$ at 300 K are particles or matter waves. The neutron scattering function measured over a broad range of reciprocal space reveals the enhanced diffraction pattern anticipated for antisymmetrized macroscopic states for protons (fermions). These features exclude a statistical distribution of protons and deuterons. Raman spectra are consistent with a mixture of KHCO$_3$ and KDCO$_3$ sublattices whose isomorphous structures are independent of the isotope content. We propose a theoretical framework for decoherence-free proton and deuteron states.

cond-mat.other↗

arXiv2009

The macroscopic quantum behavior of protons in the KHCO_3 crystal: Theory and experiments

For hydrogen bonded crystals exhibiting proton transfer along hydrogen bonds, namely $\mathrm{O1-H}... \mathrm{O2} \longleftrightarrow \mathrm{O1}... \mathrm{H-O2}$, there is a dichotomy of interpretation consisting in that while the crystal lattice is a quantum object with discrete vibrational states, protons are represented by a statistical distribution of classical particles with definite positions and momenta at any time. We propose an alternative theoretical framework for decoherence-free macroscopic proton states. The translational invariance of the crystal, the adiabatic separation of proton dynamics from that of heavy atoms, the nonlocal nature of proton states, and quantum interferences, are opposed to statistical distributions and semiclassical dynamics. We review neutron scattering studies of the crystal of potassium hydrogen carbonate (KHCO$_3$) supporting the existence of macroscopic quantum correlations, from cryogenic to room temperatures. In addition, quantum fluctuations calculated for superposition states in thermal equilibrium are consistent with measurements of the correlation time. There is no temperature induced transition from the quantum to the classical regime. The crystal can be therefore represented by a state vector and the dichotomy of interpretation must be abandoned.

cond-mat.other↗

arXiv2009

Where are Protons and Deuterons in KH_pD_{1-p}CO_3? A Neutron Diffraction Study

The crystals of potassium hydrogen carbonate (KHCO3) and the KDCO3 analogue are isomorphous. They are composed of hydrogen or deuterium bonded centrosymmetric dimers (HCO3-)(2) or (DCO3-)(2). The space group symmetry of KHpD1-pCO3 (p approximate to 0.75) determined with neutron diffraction is identical to those of KHCO3 and KDCO3. This is at variance with a random distribution of H and D nuclei. These crystals are macroscopic quantum systems in which protons or/and deuterons merge into macroscopic states.

cond-mat.other↗

arXiv2008

Nonlocal protons and deuterons opposed to disorder: a single-crystal neutron diffraction study of KH0.76D0.24CO3 and a theoretical framewok

We show with neutron diffraction that a single-crystal of potassium hydrogen deuterium carbonate at room temperature, namely KH$_{0.76}$D$_{0.24}$CO$_3$, is isomorphous with the KHCO$_3$ and KDCO$_3$ derivatives. Protons and deuterons are not disordered particles located at definite sites and Bragg peaks are best fitted with separate H and D sublattices. We propose a theoretical framework for nonlocal observables and macroscopic states compatible with the crystal field.

cond-mat.other↗

arXiv2008

A neutron diffraction study of macroscopically entangled proton states in the high temperature phase of the KHCO3 crystal at 340 K

We utilize single-crystal neutron diffraction to study the $C2/m$ structure of potassium hydrogen carbonate (KHCO$_3$) and macroscopic quantum entanglement above the phase transition at $T_c = 318$ K. Whereas split atom sites could be due to disorder, the diffraction pattern at 340 K evidences macroscopic proton states identical to those previously observed below $T_c$ by F. Fillaux et al., (2006 \textit{J. Phys.: Condens. Matter} \textbf{18} 3229). We propose a theoretical framework for decoherence-free proton states and the calculated differential cross-section accords with observations. The structural transition occurs from one ordered $P2_1/a$ structure ($T < T_c$) to another ordered $C2/m$ structure. There is no breakdown of the quantum regime. It is suggested that the crystal is a macroscopic quantum object which can be represented by a state vector. Raman spectroscopy and quasi-elastic neutron scattering suggest that the $|C2/m>$ state vector is a superposition of the state vectors for two $P2_1/a$-like structures symmetric with respect to $(a,c)$ planes.

cond-mat.other↗