Minimal Coupling Research Articles

Dynamics of certain Euler-Bernoulli rods and rings from a minimal coupling quantum isomorphism.

In some parameter and solution regimes, a minimally coupled nonrelativistic quantum particle in one dimension is isomorphic to a much heavier, vibrating, very thin Euler-Bernoulli rod in three dimensions with ratio of bending modulus to linear density (ℏ/2m)^{2}. For m=m_{e}, this quantity is comparable to that of a microtubule. Axial forces and torques applied to the rod play the role of scalar and vector potentials, respectively, and rod inextensibility plays the role of normalization. We show how an uncertainty principle ΔxΔp_{x}≳ℏ governs transverse deformations propagating down the inextensible, force and torque-free rod, and how orbital angular momentum quantized in units of ℏ or ℏ/2 (depending on calculation method) emerges when the force and torque-free inextensible rod is formed into a ring. For torqued rings with large wave numbers, a "twist quantum" appears that is somewhat analogous to the magnetic flux quantum. These and other results are obtained from a purely classical treatment of the rod, i.e., without quantizing any classical fields.

75-LB: CT-388, a Novel Once-Weekly Dual GLP-1 and GIP Receptor Modulator, Is Safe, Well-Tolerated, and Produces More than 8% Weight Loss in Four Weeks in Overweight and Obese Adults

GLP-1 and GIP can deliver complementary pharmacology when combined. CT-388 is a biased dual GLP-1 and GIP receptor modulator that exhibits no to minimal β-arrestin coupling at either receptor, designed for once-weekly subcutaneous dosing. A Phase 1, randomized, placebo-controlled, double-blind study was conducted where single ascending doses (0.5-7.5 mg) and multiple ascending doses (MAD; doses 5-12 mg via titration in 3 cohorts) for 4 weeks were administered to overweight/obese adults. Primary objective was to investigate safety and tolerability of CT-388. Total of 64 participants (men/women: 28/36; median age/BMI: 34 years/33 kg/m2) received at least 1 dose of CT-388 or placebo. PK profile was investigated over a wide dose range (0.5-12 mg) and supports once-weekly administration. Percent change in body weight from baseline at Day 29 was dose responsive and significantly greater in CT-388 treated participants versus placebo (p <0.0001) across the 3 MAD cohorts with Least Square Mean difference [95% CI] of -4.8% [-6.3, -3.3], -6.4% [-7.8, -5.0], and -8.5% [-10.4, -6.7]. Mean percent decrease from baseline at Day 23 in fasting glucose (↓8-10%), insulin (↓20-26%), HOMA-IR (↓26-33%), AUC0-120min glucose (↓26-28%) and AUC0-120min insulin (↓33-58%) during oGTT were seen in cohorts dosed up to 12 mg CT-388, suggestive of improved insulin sensitivity. Over the 4-week treatment period, CT-388 was generally well tolerated with no treatment-related discontinuations. The most frequent side effects reported were gastrointestinal (decreased appetite, nausea, vomiting, diarrhea), which were mostly mild in severity. In summary, CT-388 delivers clinically meaningful weight loss and metabolic control with a favorable tolerability profile. These data warrant further clinical evaluation of CT-388, possibly with minimal to no titration, for the treatment of obesity, T2DM, and other weight-related comorbidities. Disclosure M. Chakravarthy: Employee; Carmot Therapeutics, Inc. F. A. Argüelles-Tello: Research Support; Carmot Therapeutics, Inc. A. A. Sun: None. M. Elliott: Employee; Carmot Therapeutics, Inc. L. Acosta: None. J. E. Rankin: None. S. K. Hansen: Board Member; Carmot Therapeutics, Inc.

A Variational Approach to Resistive General Relativistic Two-Temperature Plasmas

We develop an action principle to construct the field equations for dissipative/resistive general relativistic two-temperature plasmas, including a neutrally charged component. The total action is a combination of four pieces: an action for a multifluid/plasma system with dissipation/resistivity and entrainment; the Maxwell action for the electromagnetic field; the Coulomb action with a minimal coupling of the four-potential to the charged fluxes; and the Einstein–Hilbert action for gravity (with the metric being minimally coupled to the other action pieces). We use a pull-back formalism from spacetime to abstract matter spaces to build unconstrained variations for the neutral, positively, and negatively charged fluid species and for three associated entropy flows. The full suite of field equations is recast in the so-called “3+1” form (suitable for numerical simulations), where spacetime is broken up into a foliation of spacelike hypersurfaces and a prescribed “flow-of-time”. A previously constructed phenomenological model for the resistivity is updated to include the modified heat flow and the presence of a neutrally charged species. We impose baryon number and charge conservation as well as the Second Law of Thermodynamics in order to constrain the number of free parameters in the resistivity. Finally, we take the Newtonian limit of the “3+1” form of the field equations, which can be compared to existing non-relativistic formulations. Applications include main sequence stars, neutron star interiors, accretion disks, and the early universe.

Momentum gauge fields from curved momentum space through Kaluza–Klein reduction

In this work we investigate the relation between curved momentum space and momentum-dependent gauge fields. While the former is a classic idea that has been shown to be tied to minimal-length models, the latter constitutes a relatively recent development in quantum gravity phenomenology. In particular, the gauge principle in momentum space amounts to a modification of the position operator of the form akin to a gauge-covariant derivative in momentum space according to the minimal coupling prescription. Here, we derive both effects from a Kaluza–Klein reduction of a higher-dimensional geometry exhibiting curvature in momentum space. The interplay of the emerging gauge fields as well as the remaining curved momentum space lead to modifications of the Heisenberg algebra. While the gauge fields imply Moyal-type noncommutativity dependent on the analogue field strength tensor, the dimensionally reduced curved momentum space geometry translates to a Snyder-type noncommutative geometry.

The characters and advantages of different algorithms in multi-robot path planning

Multi-agent path finding (MAPF) issue has recently gained popularity, with the goal of planning for several agents who can all follow instructions at the same time without colliding. It is a common difficulty when attempting to identify pathways to several agents while ensuring that each agent reaches its destination without colliding and confusion. Real-world MAPF applications such as warehouse management, food, and beverage distribution, and aviation management are paid a number of attention from people in recent years. This article discusses centralized and decentralized techniques in MAPF challenges. Several traditional algorithms will be quoted and introduced through the help of some past papers and experiments. Finally, it was determined that decentralized strategies generally provide more powerful performance, whereas centralized strategies are generally capable of computing optimal solution sequences with minimal coupling and solving complex problems, ranging from relatively few robot problems with high coupling to many robot problems with low coupling.

Galaxy rotation curves in the f(R, T) gravity formalism

Astronomical data have shown that the Galaxy rotation curves are mostly flat in the far distance of the galactic cores, which could reveal the insufficiency of our knowledge about how gravity works in these regimes. In this paper we introduce a resolution of this issue from the f(R, T) modified gravity formalism perspective. By investigating two classes of models with separable (minimal coupling model) and inseparable (non-minimal coupling model) parts of the Ricci scalar R and trace of the energy-momentum tensor T, we find that only in the latter models it is possible to attain flat galaxy rotation curves. Remarkably, those are obtained with no need for dark matter, which can be seen as an f(R, T) gravity advantage, since we still have not probed dark matter particles in laboratory.

Hamiltonian facets of classical gauge theories on E-manifolds

Manifolds with boundary, with corners, b-manifolds and foliations model configuration spaces for particles moving under constraints and can be described as E-manifolds. E-manifolds were introduced in Nest and Tsygan (2001 Asian J. Math. 5 599–635) and investigated in depth in Miranda and Scott (2021 Rev. Mat. Iberoam. 37 1207–24). In this article we explore their physical facets by extending gauge theories to the E-category. Singularities in the configuration space of a classical particle can be described in several new scenarios unveiling their Hamiltonian aspects on an E-symplectic manifold. Following the scheme inaugurated in Weinstein (1978 Lett. Math. Phys. 2 417–20), we show the existence of a universal model for a particle interacting with an E-gauge field. In addition, we generalise the description of phase spaces in Yang–Mills theory as Poisson manifolds and their minimal coupling procedure, as shown in Montgomery (1986 PhD Thesis University of California, Berkeley), for base manifolds endowed with an E-structure. In particular, the reduction at coadjoint orbits and the shifting trick are extended to this framework. We show that Wong’s equations, which describe the interaction of a particle with a Yang–Mills field, become Hamiltonian in the E-setting. We formulate the electromagnetic gauge in a Minkowski space relating it to the proper time foliation and we see that our main theorem describes the minimal coupling in physical models such as the compactified black hole.

Information entropy of nuclear electromagnetic transitions in AdS/QCD

Electromagnetic transitions involving nucleons and their resonances are here presented in the fermionic sector of the AdS/QCD soft-wall model, using the differential configurational entropy (DCE) as a measure of information entropy. The DCE is employed to derive adjustable parameters that define the minimal and nonminimal couplings in the nuclear interaction with a gauge vector field, in the nucleonic γN→N⁎(1535) transition. The values obtained comply with phenomenological data with good accuracy.

Divergence-Conforming Velocity and Vorticity Approximations for Incompressible Fluids Obtained with Minimal Facet Coupling

We introduce two new lowest order methods, a mixed method, and a hybrid discontinuous Galerkin method, for the approximation of incompressible flows. Both methods use divergence-conforming linear Brezzi–Douglas–Marini space for approximating the velocity and the lowest order Raviart–Thomas space for approximating the vorticity. Our methods are based on the physically correct viscous stress tensor of the fluid, involving the symmetric gradient of velocity (rather than the gradient), provide exactly divergence-free discrete velocity solutions, and optimal error estimates that are also pressure robust. We explain how the methods are constructed using the minimal number of coupling degrees of freedom per facet. The stability analysis of both methods are based on a Korn-like inequality for vector finite elements with continuous normal component. Numerical examples illustrate the theoretical findings and offer comparisons of condition numbers between the two new methods.

Exact duality and local dynamics in SU(N) lattice gauge theory

We construct exact duality transformations in pure SU(N) Hamiltonian lattice gauge theory in ($2+1$) dimension. This duality is obtained by making a series of iterative canonical transformations on the SU(N) electric vector fields and their conjugate magnetic vector potentials on the four links around every plaquette. The resulting dual description is in terms of the magnetic scalar fields or plaquette flux loops and their conjugate electric scalar potentials. Under SU(N) gauge transformations they both transform like adjoint matter fields. The dual Hamiltonian describes the nonlocal self-interactions of these plaquette flux loops in terms of the electric scalar potentials and with inverted coupling. We show that these nonlocal loop interactions can be made local and converted into minimal couplings by introducing SU(N) auxiliary gauge fields along with new plaquette constraints. The matter fields can be included through minimal coupling. The techniques can be easily generalized to ($3+1$) dimensions.

Uncertainty optimization based on sensitivity analysis for TSOM method in multi-measurands metrology

Semiconductor manufacturing usually requires precise measurements on critical geometric parameters of those nano-scaled targets to perform the process control and promote the yields. Theoretically through-focus scanning optical microscopy (TSOM) method enables to extract measurement results with 3D nano-scaled resolution via searching for the solution leading to the minimal errors between simulated and experimented output images (so-called TSOM images) from the possible solution spaces of the measurands. However, the coupling effects among the measurands increase the uncertainties of the results, which hinders TSOM method in the multi-measurands metrology. Since the coupling effects can be decreased via optimizing measurement conditions, this paper proposes an optimization method based upon the sensitivity analysis. This method samples all the measurands to generate the coupling factors that quantitatively characterize the coupling effects and selects the optimized measurement condition which corresponds to the minimal coupling effects. The selected measurement condition is verified by a measurement on three Au lines, and the results prove that this condition leads to nano-scaled measuring errors and uncertainties. Contrary to local optimizations, the proposed method is valid for both linear and nonlinear measurement models, and can be generalized to other model-based metrologies.

On the uniqueness of Einstein-Cartan theory: Lagrangian, covariant derivative and equation of motion

In the standard Einstein-Cartan theory, matter fields couple to gravity through the Minimal Coupling Procedure (MCP), and yet leave the theory an ambiguity. Applying MCP to the action or to the equation of motion would lead to different gravitational couplings. We propose a new covariant derivative to remove the ambiguity and discuss the relation between our proposal and previous treatments on this subject.

Multipolar quantum electrodynamics of localized charge-current distributions: Spectral theory and renormalization

We formulate a nonrelativistic quantum field theory to model interactions between quantized electromagnetic fields and localized charge-current distributions. The electronic degrees of freedom are encoded in microscopic polarization and magnetization field operators whose moments are identified with the multipole moments of the charge-current distribution. The multipolar Hamiltonian is obtained from the minimal coupling Hamiltonian through a unitary transformation, often referred to as the Power-Zienau-Woolley transformation; we renormalize this Hamiltonian using perturbation theory, the result of which is used to compute the leading-order radiative corrections to the electronic energy levels due to interactions between the electrons and quantum vacuum fluctuations in the electromagnetic field. Our renormalized energy shift constitutes a generalization of the Lamb shift in atomic hydrogen, valid for general localized assemblies of atoms and molecules, possibly with net charge but absent a free current. By expanding the fields in a series of multipole moments, our results can be used to study contributions to this energy shift coming from specific multipole moments of arbitrary order.

On the non-minimal coupling of magnetic fields with gravity in Schwarzschild spacetime

In this work we study the effects of non-minimal coupling between electromagnetism and gravity, which are motivated by quantum effects such as vacuum polarization. We investigate the modification of both asymptotically dipole and uniform magnetic fields around a Schwarzschild black hole that come as the result of non-minimal coupling. While in both cases the magnetic field gets enhanced or suppressed with respect to the case of minimal coupling, depending on the sign of non-minimal coupling parameter, in the case of a background uniform magnetic field the direction of the magnetic field also alters in the vicinity of the black hole horizon. We have discussed the possible astrophysical and cosmological sources for which the vacuum polarization may be at play, while also discussing the observational effects, in particular the possibility of synchrotron radiation from the vicinity of a black hole. We conclude that such observations could be used to constrain the value of the non-minimal coupling parameter.

Spin-Electric Coupling in Lead Halide Perovskites.

Lead halide perovskites enjoy a number of remarkable optoelectronic properties. To explain their origin, it is necessary to study how electromagnetic fields interact with these systems. We address this problem here by studying two classical quantities: Faraday rotation and the complex refractive index in a paradigmatic perovskite CH_{3}NH_{3}PbBr_{3} in a broad wavelength range. We find that the minimal coupling of electromagnetic fields to the k·p Hamiltonian is insufficient to describe the observed data even on the qualitative level. To amend this, we demonstrate that there exists a relevant atomic-level coupling between electromagnetic fields and the spin degree of freedom. This spin-electric coupling allows for quantitative description of a number of previous as well as present experimental data. In particular, we use it here to show that the Faraday effect in lead halide perovskites is dominated by the Zeeman splitting of the energy levels and has a substantial beyond-Becquerel contribution. Finally, we present general symmetry-based phenomenological arguments that in the low-energy limit our effective model includes all basis coupling terms to the electromagnetic field in the linear order.

Newton versus Coulomb for Kaluza–Klein modes

We consider a set of elementary compactifications of D+1 to D spacetime dimensions on a circle: first for pure general relativity, then in the presence of a scalar field, first free then with a non minimal coupling to the Ricci scalar, and finally in the presence of gauge bosons. We compute the tree-level amplitudes in order to compare some gravitational and non-gravitational amplitudes. This allows us to recover the known constraints of the U(1), dilatonic and scalar weak gravity conjectures in some cases, and to show the interplay of the different interactions. We study the KK modes pair-production in different dimensions. We also discuss the contribution to some of these amplitudes of the non-minimal coupling in higher dimensions for scalar fields to the Ricci scalar.

Scrambling and entangling spinning particles

In this paper we revisit the gravitational eikonal amplitudes of two scattering spinning particles and inspect their scrambling power in the spin spaces that is quantified through the tripartite information. We found that in the non-relativistic limit and a special high-energy limit the leading contribution is a quantity that is universal and theory independent. The minimal coupling is singled out with minimal scrambling in a different high momenta limit. We also inspected the initial state dependence of entanglement generation and found that the spin coherent state with vanishing spin may not necessarily be the hardest to entangle. Interestingly, among a family of mixed states, the only P-rep state there known to be the best approximation of classical mixed states was singled out as one with minimal entanglement generated.

Relativistic Wormholes in Extended Teleparallel Gravity with Minimal Matter Coupling

AbstractThis study explores the wormhole solutions utilizing the notion of conformal symmetry in the background of the gravity. The exact shape functions are calculated using the Gaussian and Lorentzian distributions as the noncommutative source of the energy density. All the energy conditions are checked for the two different shape functions. The presence of exotic matter is confirmed due to the violation of the null energy conditions. The physical aspects of the epicyclic frequencies of test particles are discussed in the spacetime geometry of the obtained wormholes in the current analysis and it is shown that how they depend on the spacetime parameters. The red‐blue shifts for the photons emitted by the orbiting test particles are also investigated and their dependence on the spacetime parameters is discussed. Further, the stability of the developed structure of the traversable wormholes is investigated by using the Tolman‐Oppenheimer‐Volkoff equation.

Coupling coordination degree of environment, energy, and economic growth in resource-based provinces of China

Environmental deterioration by natural resources development has emerged as an important concern recently. To address this concern, we constructed a tri-system evaluation index for environment, energy, and the economy and used the entropy value method and the coupling coordination degree model to analyze spatiotemporal changes in the coupling and coordination of subsystems in 10 of China's resource-based regions between 2011 and 2020 and found that the coupling and coordination level of the energy–economy–environment (3E) system in China's resource-based regions is characterized by fluctuating growth with an overall positive developmental trend. The average coupling coordination level increased from 0.541 in 2011 to 0.643 in 2020, reaching the primary coupling coordination stage. Clear heterogeneity exists between various resource-based regions: eastern regions perform better than western, and western better than central. Eastern regions Guangdong, Shandong, and Tianjin achieved coordinated development, while Liaoning exhibits the lowest coupling coordination level. The western regions vary considerably: Shanxi exhibits the highest degree of primary coupling coordination, whereas Qinghai, on the verge of dysfunctional recession, exhibits the lowest. The central regions vary the least; all exhibit minimal coupling coordination. These facts indicate that to enhance the coupling coordination level of China's 3E system in an integrated manner, each region must formulate a differentiated optimization strategy to compensate for its developmental shortcomings.

Constant-roll inflation from non-commutative geometry viewpoint

In this paper, we consider an inflation scenario in which the inflation roll rate, defined by [Formula: see text] is supposed to be constant and study constant-roll inflation by a scalar field with minimal coupling to gravity in the presence of non-commutative (NC) parameters. For this purpose, we use the deformation approach and obtain the corresponding Lagrangian to the model by employing new variables. Then, we find exact solutions for the inflation potential, which include power-law, quadratic hilltop, and natural inflation. Further, we discuss the effect of parameters on the inflation model in NC space.