Quantum Mechanical Origin Research Articles

Kitaev interactions through extended superexchange pathways in the jeff=1/2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${j}_{{\\mathsf{eff}}}=1/2$$\\end{document} Ru3+ honeycomb magnet RuP3SiO11

Magnetic materials are composed of the simple building blocks of magnetic moments on a crystal lattice that interact via magnetic exchange. Yet from this simplicity emerges a remarkable diversity of magnetic states. Some reveal the deep quantum mechanical origins of magnetism, for example, quantum spin liquid (QSL) states in which magnetic moments remain disordered at low temperatures despite being strongly correlated through quantum entanglement. A promising theoretical model of a QSL is the Kitaev model, composed of unusual bond-dependent exchange interactions, but experimentally, this model is challenging to realise. Here we show that the material requirements for the Kitaev QSL survive an extended pseudo-edge-sharing superexchange pathway of Ru3+ octahedra within the honeycomb layers of the inorganic framework solid, RuP3SiO11. We confirm the requisite jeff=12\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${j}_{{\\mathsf{eff}}}=\\frac{1}{2}$$\\end{document} state of Ru3+ in RuP3SiO11 and resolve the hierarchy of exchange interactions that provide experimental access to an unexplored region of the Kitaev model.

Relic gravitons and non-stationary processes

Stationary processes do not accurately describe the diffuse backgrounds of relic gravitons whose correlations are homogeneous in space (i.e. only dependent upon the distance between the two spatial locations) but not in time. The symmetries of the autocorrelations ultimately reflect the quantum mechanical origin of the diffuse backgrounds and lead to non-stationary observables at late time. In particular, large oscillations are believed to arise in the spectral energy density that is customarily (but approximately) related to the tensor power spectrum. When the full expression of the spectral energy density is employed the amplitudes of oscillation are instead suppressed in the large-scale limit and the non-stationary features of the late-time signal practically disappear. For similar reasons the relations between the spectral energy density and the spectral amplitude are ambiguous in the presence of non-stationary features. While it is debatable if the non-stationary features are (or will be) directly detectable, we argue that the spectral amplitude following from the Wiener-Khintchine theorem is generally inappropriate for a consistent description of the relic signal. Nevertheless the strong oscillatory behaviour of the late-time observables is naturally smeared out provided the spectral energy density is selected as pivotal variable.

Evolution of coupled scalar perturbations through smooth reheating. Part I. Dissipative regime

If the inflaton is a heavy scalar field, it may equilibrate slower thansome other degrees of freedom, e.g. non-Abelian gauge bosons. In this case,perturbations in the inflaton field and in a thermalplasma coexist from a given moment onwards. We derive a gauge-invariant setof three coupled equations governing the time evolution of such a system.Despite singular coefficients,a reliable numerical solution can be obtained for a longtime period, starting from phase oscillations inside the Hubble horizon,and extending until acoustic oscillations in a radiation-dominated universe.Benchmarks are illustrated from a “weak regime”,where perturbations have a quantum-mechanical origin but get dissipatedby interactions with the plasma. Among applications of our formalismcould be inhomogeneity-induced nucleations inpost-inflationary phase transitions, andthe production of scalar-induced gravitational waves.

Mass Interaction Principle as a Foundational Framework for Quantum Mechanics

This paper proposes mass interaction principle (MIP) as: the particles will be subjected to the random frictionless Brownian motion by the collision of space time particle(STP) ubiquitous in spacetime. The change in the amount of action of the particles during each collision is an integer multiple of the Planck constant h. The motion of particles under the action of STP is a Markov process. Under this principle, we infer that the statistical inertial mass of a particle is a statistical property that characterizes the difficulty of particle diffusion in spacetime. Within the framework of MIP, all the essences of quantum mechanics are derived, which proves that MIP is the origin of quantum mechanics. Due to the random collisions between STP and the matter particles, matter particles are able to behave exactly as required by the supervisor and shepherd for all microscopic behaviors of matter particles. More importantly, we solve a world class puzzle about the anomalous magnetic moment of muon in the latest experiment,and give a self-consistent explanation to the lifetime discrepancy of muon between standard model prediction and experiments at the same time. Last but not least, starting from MIP, we prove the principle of entropy increasing and clarify the physical root of entropy at absolute zero. Within the framework of MIP, we comprehensively discussed the Copenhagen interpretation. It leads to an important conclusion that Copenhagen interpretation is unnecessary for the quantum mechanical system. We found that Maxwell’s classical electromagnetic theory is applicable to the microscopic world not as previously thought. The key is that Brownian motion and classical electromagnetic theory must be combined together to completely solve the problem of electrons outside the nucleus not radiating electromagnetic waves.

Dichroism of plasmonic chiral nanoalloys by rational design.

Time-dependent density functional theory (TDDFT) simulations are conducted on a series of chiral gold/silver alloy nanowires to explore whether silver doping can produce an enhancement of circular dichroism at the plasmon resonance in these systems, and to identify the quantum-mechanical origin of the observed effects. We find a strong plasmonic dichroism when one or two helixes of gold atoms are substituted by silver in a linear chiral nanotube, whose pure gold counterpart does not display any plasmonic dichroism, and we rationalize this finding in terms of "decoupling" the destructive interference of excitations in the pure gold nanotube via alloying. However, further attempts to increase the plasmonic dichroism by considering multi-shell gold nanowires in which one entire shell is doped with silver did not produce the desired effect, but rather a decrease in circular dichroism. We show that this latter result is due to a more severe destructive interference in the dipole excitation contributions, and suggest that further amplification should be possible in principle by properly tuning simultaneously the nanowire structure and chemical ordering.

On the Origin and Unification of Electromagnetism, Gravitation, and Quantum Mechanics

On the Origin and Unification of Electromagnetism, Gravitation, and Quantum Mechanics

Nanostructures as the Substrate for Single-Molecule Magnet Deposition.

Anchoringsingle-molecule magnets (SMMs) on the surface of nanostructures is gaining particular interest in the field of molecular magnetism. The accurate organization of SMMs on low-dimensional substrates enables controlled interactions and the possibility of individual molecules' manipulation, paving the route for a broad range of nanotechnological applications. In this comprehensive review article, the most studied types of SMMs are presented, and the quantum-mechanical origin of their magnetic behavior is described. The nanostructured matrices were grouped and characterized to outline to the reader their relevance for subsequent compounding with SMMs. Particular attention was paid to the fact that this process must be carried out in such a way as to preserve the initial functionality and properties of the molecules. Therefore, the work also includes a discussion of issues concerning both the methods of synthesis of the systems in question as well as advanced measurement techniques of the resulting complexes. A great deal of attention was also focused on the issue of surface-molecule interaction, which can affect the magnetic properties of SMMs, causing molecular crystal field distortion or magnetic anisotropy modification, which affects quantum tunneling or magnetic hysteresis, respectively. In our opinion, the analysis of the literature carried out in this way will greatly help the reader to design SMM-nanostructure systems.

Quantum heat machines enabled by twisted geometry

In this paper, we analyze the operation of an Otto cycle heat machine driven by a non-interacting two-dimensional electron gas on a twisted geometry. We show that due to both the energy quantization on this structure and the adiabatic transformation of the number of complete twists per unit length of a helicoid, the machine performance in terms of output work, efficiency, and operation mode can be altered. We consider the deformations as in a spring, which is either compressed or stretched from its resting position. The realization of classically inconceivable Otto machines, with an incompressible sample, can be realized as well. The energy-level spacing of the system is the quantity that is being either compressed or stretched. These features are due to the existence of an effective geometry-induced quantum potential which is of pure quantum-mechanical origin.

Quantum origins of scalar gravitational waves: Exploring the conformal factor in scalar–tensor theory of gravity

Delving into the realm of scalar–tensor theory of gravity, this paper uncovers the intricate details of the conformal factor and its correspondence to quantum mechanical mass fluctuations. Shedding light on the theory’s key findings, we explore the quantum mechanical nature of the wave equation associated with mass fluctuations, predicting the creation of scalar gravitational waves. The association of conformal fluctuations with the quantum potential presents a remarkable feature of this theory, which predicts a scalar component of gravitational waves. With the potential to generate such waves in a laboratory set-up, this theory invites exciting possibilities for empirical testing, highlighting the quantum mechanical origin of scalar gravitational waves.

Magnetotransport in the double-atomic-layer rect-7×3-In phase on Si(111)

Magnetoresistance of the double-atomic-layer $\text{rect-}\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\text{-In}/\mathrm{Si}(111)$ phase was measured in situ using the four-point-probe technique in the temperature range from 2.5 to 33 K and magnetic fields from $\ensuremath{-}8$ to $+8$ T. The $\text{rect-}\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\text{-In}/\mathrm{Si}(111)$ was found to demonstrate a classical quadratic behavior of magnetoresistance at fields lower than $\ensuremath{\sim}0.2$ T, and a large positive linear magnetoresistance at fields up to 8 T in the low-temperature range of up to $\ensuremath{\sim}10$ K. In contrast, the results obtained on the parent single- and double-atomic In layers formed on the ${\mathrm{NiSi}}_{2}/\text{Si}(111)$ substrate show much lower values of magnetoresistance. In view of the density functional theory calculation results, which reveal the presence of tiny Fermi pockets in the $\text{rect-}\sqrt{7}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\text{-In/Si}(111)$ electronic band structure, we attribute the observed large linear magnetoresistance at the low-temperature range to a quantum mechanical origin.

Ultrafast opto-protonics in a hydrogen-bonded π-molecular ferroelectric crystal

We investigated the ultrafast photo-response of a ferroelectric co-crystal of Hdppz–Hca composed of protonated 2,3-di (2-pyridinyl)pyrazine (Hdppz) and deprotonated chloranilic acid (Hca). Whereas the intermolecular proton transfer triggers the ferroelectricity in Hdppz–Hca, the majority of the large spontaneous polarization has a quantum mechanical origin from the highly polarizable π-electron system. In this study, we prepared a carrier-envelope phase-stable mid-infrared pulse tuned to the proton vibration of this system and investigated the time dependence of the subsequent change in the second harmonic generation (SHG) yield. By exciting the proton vibration, the relative change in SHG yield increased by about 100%, and the enhancement was only observed within the duration of the applied electric field. The huge enhancement and ultrafast response of the SHG, which is not seen in usual ferroelectrics, is attributed to the fact that the photoexcitation dynamically changes the stable position of protons and π-electrons, resulting in an ultrafast increase in the value of χ(2) of Hdppz–Hca. The phenomena observed here indicate a new property of this system as a quantum material with nonlinearity and can be regarded as opto-protonics in proton-mediated ferroelectrics.

Effect of disorder on thermodynamic instability of binary Rare-earth – Nickel – Palladium compounds

We have investigated the thermodynamic stability of disordered rare-earth phases SmX2 and Sm10X21 (X=Ni, Pd) using machine-learning based analytical descriptor and first-principles density functional theory methods. The absence of Laves phase compounds in R-Pd binary systems is a longstanding problem of rare earth science: even though Ni and Pd belong to the same group of the periodic table and have similar electronic structure, the Pd compound crystallizes in a monoclinic (C2/m) phase with 10:21 stoichiometry, i.e., Sm10Pd21, while the Ni compound adopts a cubic Laves phase (MgCu2) structure. To understand this contrasting phase stability, we performed thermodynamic convex hull analysis of SmxNi1-x and SmxPd1-x binary systems, which is experimentally validated using powder X-ray diffraction (PXRD) analyzes of polycrystalline Sm(NixPd1-x)2 samples with x=0, 0.5, and 1. A detailed electronic-structure (band-structure, charge density, and Fermi-surface) analysis of the differences between SmNi2/SmPd2 and Sm10Ni21/Sm10Pd21 compounds provides the quantum mechanical origin of the unfavorable mixing of Pd with Ni in cubic Laves phase. We show that the stability of Sm-Pd in 10:21 stoichiometry arises from improved intra-/inter-layer 5d-4d bonding compared to the 1:2 stoichiometry. Our work emphasizes the importance of ab-initio methods and computationally inexpensive analytical descriptors for the detailed analysis of thermodynamic and electronic properties of hard-to-prepare rare-earth compounds.

Anomaly-induced sound absorption in Weyl semimetals

Topology of Weyl semimetals affects sound attenuation in these materials. Most notably, the existence of Berry monopoles associated with linear band crossings leads to the existence of acoustic magnetochiral dichroism: sound attenuation is different for opposite directions of sound propagation. The effect is within reach of current experimental techniques, and, importantly, is of quantum mechanical origin. This should help its detection in available compounds.

Circularly Polarized Plasmons in Chiral Gold Nanowires via Quantum-Mechanical Design.

Time-dependent density functional theory (TDDFT) simulations are conducted on a series of chiral gold nanowires to explore whether an enhancement of circular dichroism at the plasmon resonance is possible and identify its quantum-mechanical origin. We find that in linear two-dimensional chiral nanowires the dichroic response is suppressed by destructive interference of nearly degenerate components with opposite signs, pointing to this phenomenon as a common and likely origin of the difficulty encountered so far in achieving a plasmonic CD response in experiment and suggesting nevertheless that these opposite components could be "decoupled" by using multiwall arrangements. In contrast, we predict a giant dichroic response for nanowires with three-dimensional helical coiling. We rationalize this finding via an electronic structure analysis of longitudinal and transversal plasmonic excitations and their coupling into chiral components, and we propose a simple formula for the chiral response as a function of structural parameters (nanowire length and coiling number).

Revival of oscillation and symmetry breaking in coupled quantum oscillators.

Restoration of oscillations from an oscillation suppressed state in coupled oscillators is an important topic of research and has been studied widely in recent years. However, the same in the quantum regime has not been explored yet. Recent works established that under certain coupling conditions, coupled quantum oscillators are susceptible to suppression of oscillations, such as amplitude death and oscillation death. In this paper, for the first time, we demonstrate that quantum oscillation suppression states can be revoked and rhythmogenesis can be established in coupled quantum oscillators by controlling a feedback parameter in the coupling path. However, in sharp contrast to the classical system, we show that in the deep quantum regime, the feedback parameter fails to revive oscillations, and rather results in a transition from a quantum amplitude death state to the recently discovered quantum oscillation death state. We use the formalism of an open quantum system and a phase space representation of quantum mechanics to establish our results. Therefore, our study establishes that the revival scheme proposed for classical systems does not always result in restoration of oscillations in quantum systems, but in the deep quantum regime, it may give counterintuitive behaviors that are of a pure quantum mechanical origin.

Fluorescence enhancement mechanism of thymolphthalein-based probe by coordination interaction with zinc ion

Although there are some proposed explanations for fluorescence enhancement of metal ions, a phenomenon with wide applications in biosensors and chemosensors, current understanding of the quantum–mechanical origin of this photophysical behaviour is limited. To address this issue, we selected thymolphthalein-based probe (T) reported recently as model system, and investigated the photochemical and photophysical properties of T and T-Zn(II) complex. The geometry structures of T and its Zn(II) complex were optimized, and the experimental absorption spectrum were well reproduced through density functional theory (DFT) methods. Furthermore, the excited state intramolecular proton transfer (ESIPT) mechanisms of T were systematically investigated. The constructed potential energy surfaces (PESs) of T at ground (S0) and first exited (S1) states indicate that, after photo-excitation, the intramolecular single-proton transfer reaction occurs more readily with the H atom removing from O to neighboring N. Furthermore, thermodynamic analysis of the T-Zn(II) complex shows that mononuclear complex (C1) is the most thermodynamically stable structure, and the intramolecular single proton transfer process of C1 is thermodynamically unfavorable at the S1 state. Time-dependent DFT calculations show that the fluorescence emission is from the S1 states of the single-proton transfer tautomer of T, as predicted from Kasha’s rule, in comparison, the fluorescence emission of Zn(II) complex is from the S1 states of T-Zn(II) rather than its single-proton transfer tautomer. The inhibitor of Zn(II) on the single proton transfer reaction plays an important role on fluorescence enhancement.

The physical origin of Schrödinger equation

Quantum mechanics is one of the basic theories of modern physics. Here, the famous Schrödinger equation and the differential operators representing mechanical quantities in quantum mechanics are derived, just based on the principle that the translation invariance (symmetry) of a system in Hamiltonian mechanics should be preserved in quantum mechanics. Moreover, according to the form of the differential operators, the commutation relation in quantum mechanics between the generalized coordinate and the generalized momentum can be directly obtained. We believe that the results in this paper are very useful for understanding the physical origin of quantum mechanics.

Barad, Bohr, and quantum mechanics

The last decade has seen an increasing number of references to quantum mechanics in the humanities and social sciences. This development has in particular been driven by Karen Barad’s agential realism: a theoretical framework that, based on Niels Bohr’s interpretation of quantum mechanics, aims to inform social theorizing. In dealing with notions such as agency, power, and embodiment as well as the relation between the material and the discursive level, the influence of agential realism in fields such as feminist science studies and posthumanism has been profound. However, no one has hitherto paused to assess agential realism’s proclaimed quantum mechanical origin including its relation to the writings of Niels Bohr. This is the task taken up here. We find that many of the implications that agential realism allegedly derives from a Bohrian interpretation of quantum mechanics dissent from Bohr’s own views and are in conflict with those of other interpretations of quantum mechanics. Agential realism is at best consistent with quantum mechanics and consequently, it does not capture what quantum mechanics in any strict sense implies for social science or any other domain of inquiry. Agential realism may be interesting and thought provoking from the perspective of social theorizing, but it is neither sanctioned by quantum mechanics nor by Bohr’s authority. This conclusion not only holds for agential realism in particular, it also serves as a general warning against the other attempts to use quantum mechanics in social theorizing.

High frequency atomic tunneling yields ultralow and glass-like thermal conductivity in chalcogenide single crystals

Crystalline solids exhibiting glass-like thermal conductivity have attracted substantial attention both for fundamental interest and applications such as thermoelectrics. In most crystals, the competition of phonon scattering by anharmonic interactions and crystalline imperfections leads to a non-monotonic trend of thermal conductivity with temperature. Defect-free crystals that exhibit the glassy trend of low thermal conductivity with a monotonic increase with temperature are desirable because they are intrinsically thermally insulating while retaining useful properties of perfect crystals. However, this behavior is rare, and its microscopic origin remains unclear. Here, we report the observation of ultralow and glass-like thermal conductivity in a hexagonal perovskite chalcogenide single crystal, BaTiS3, despite its highly symmetric and simple primitive cell. Elastic and inelastic scattering measurements reveal the quantum mechanical origin of this unusual trend. A two-level atomic tunneling system exists in a shallow double-well potential of the Ti atom and is of sufficiently high frequency to scatter heat-carrying phonons up to room temperature. While atomic tunneling has been invoked to explain the low-temperature thermal conductivity of solids for decades, our study establishes the presence of sub-THz frequency tunneling systems even in high-quality, electrically insulating single crystals, leading to anomalous transport properties well above cryogenic temperatures.

Classical universe arising from quantum cosmology

In this paper, we study the classical limit and unitary evolution of quantum cosmology by applying the Weyl--Wigner--Groenewold--Moyal formalism of deformation quantization to quantum cosmology of a homogeneous and isotropic universe with positive spatial curvature and conformally coupled scalar field. The corresponding quantum cosmology (similar to the Schr\"{o}dinger interpretation in canonical quantization scheme of quantum cosmology) is described by the Moyal--Wheeler--DeWitt equation which has an exact solution in Moyal phase space, resulting in Wigner quasiprobability distribution function, peaking over the classical solutions. We show that for a large value of the quantum number $n$, the emerged classical universe is filled with radiation with quantum mechanical origin. Also, we introduce a canonical transformation on the scalar field sector of the model such that the conjugate momenta of the new canonical variable appear linearly in the transformed total Hamiltonian. Using this canonical transformation, we show that, it may lead to disentangle the time from the true dynamical variables. We obtain the time-dependent Wigner function for a coherent as well as for squeezed states. We show that the peak of these Wigner functions follows the classical trajectory in the phase space.