Low-energy Action Research Articles

Effect of a low-energy action on the surface of metallic alloys

The influence of magnetic-pulse fields on the surfaces of ironand titanium-based alloys is analyzed. It is shown that magnetic-pulse treatment has a complex effect on the surface.

Low energy CID and action IRMPD provide insights into a minor subpopulation of the gas-phase conformers of triply charged bradykinin

Unique fragmentation of the IMS-resolved conformers of triply charged bradykinin is shown to occur at very low collision energies by quadrupole CID. For the major C conformation of bradykinin, the unique fragmentation appears to result from a subpopulation that has a different average CCS than the dominant C population that has been previously identified as TTC (trans, trans, cis at the three Pro residues). The three major gas-phase isomers exhibit minimal differences in fragmentation at collision energies greater than 12eV, presumably because the amide bonds of the proline residues isomerize prior to dissociation at these higher energies. The differences in fragmentation observed in the low collision energy regime (<12eV) are attributed to the conformational differences of the fragmenting subpopulations of the mobility resolved populations associated with the cis or trans isomerization state of the three proline residues. Action IRMPD of the b2 ion supports a cis-Pro2 isomerization state for the subpopulation of conformation C fragmenting at low energies, assuming no isomerization was induced by the low energy CID. Substitution of N-methyl alanine, an acyclic proline mimic, independently, for each of the three prolines of bradykinin and low energy fragmentation of the minor subpopulation of conformation C allowed for tentative assignments of the isomerization state of two of the three proline resides of this subpopulation. Density functional theory calculations support the conclusion made from NMA-substitutions and together suggest that the subpopulation of conformation C is cis at Pro2 and trans at Pro7. It is not clear whether the minor subpopulation is a typical feature of triply charged bradykinin or whether unintended activation in the instrument used here produces this population. The results illustrate the utility of ion mobility coupled with low-energy CID for the determination of a minor subpopulation that was not visible by MS or IM alone.

Coherent Correlated States of Interacting Particles -The Possible Key to Paradoxes and Features of LENR

In this article, the universal mechanism of optimization of low energy nuclear reactions (LENR) on the basis of coherent correlated states (CCS) of interacting particles is discussed. Formation of these states is the result of special nonstationary low energy action to parameters of potential well containing interacting particles. It was shown that in real nuclear-physical systems usage of CCS leads to sharp growth (up to 10 30 -10 100 and more) of Coulomb barrier penetrability at very low energy of interacting particles. Several successful LENR experiments based on CCS are discussed.

Who you gonna call? Runaway ghosts, higher derivatives and time-dependence in EFTs

We briefly review the formulation of effective field theories (EFTs) in time-dependent situations, with particular attention paid to their domain of validity. Our main interest is the extent to which solutions of the EFT capture the dynamics of the full theory. For a simple model we show by explicit calculation that the low-energy action obtained from a sensible UV completion need not take the restrictive form required to obtain only second-order field equations, and we clarify why runaway solutions are nevertheless typically not a problem for the EFT. Although our results will not be surprising to many, to our knowledge they are only mentioned tangentially in the EFT literature, which (with a few exceptions) largely addresses time-independent situations.

Thermodynamic properties of asymptotically Reissner–Nordström black holes

Motivated by possible relation between Born–Infeld type nonlinear electrodynamics and an effective low-energy action of open string theory, asymptotically Reissner–Nordström black holes whose electric field is described by a nonlinear electrodynamics (NLED) are studied. We take into account a four dimensional topological static black hole ansatz and solve the field equations, exactly, in terms of the NLED as a matter field. The main goal of this paper is investigation of thermodynamic properties of the obtained black holes. Moreover, we calculate the heat capacity and find that the nonlinearity affects the minimum size of stable black holes. We also use Legendre-invariant metric proposed by Quevedo to obtain scalar curvature divergences. We find that the singularities of the Ricci scalar in Geometrothermodynamics (GTD) method take place at the Davies points.

Coherent correlated states and low-energy nuclear reactions in non stationary systems

In this paper the universal mechanism of optimization of low-energy nuclear reactions on the basis of coherent correlated states of interacting particles is discussed. The formation of these states is the result of the special nonstationary low-energy action to any one of these interacting particles. We have considered the peculiarities and investigated the efficiency of the creation of a correlated state under monotonous or periodic action on the particle that is situated in the parabolic potential. This method is shown to lead to the rapid formation of a strongly correlated particle state that provides an almost complete clearing of the potential barrier even for a narrow range of oscillator frequency variations. The successful low-energy fusion experiment based on the use of correlated states of interacting particles at laser irradiation is discussed.

Structure in 6D and 4D $ \mathcal{N}=1 $ supergravity theories from F-theory

We explore some aspects of 4D supergravity theories and F-theory vacua that are parallel to structures in the space of 6D theories. The spectrum and topological terms in 4D supergravity theories correspond to topological data of F-theory geometry, just as in six dimensions. In particular, topological axion-curvature squared couplings appear in 4D theories; these couplings are characterized by vectors in the dual to the lattice of axion shift symmetries associated with string charges. These terms are analogous to the Green-Schwarz terms of 6D supergravity theories, though in 4D the terms are not generally linked with anomalies. We outline the correspondence between F-theory topology and data of the corresponding 4D supergravity theories. The correspondence of geometry with structure in the low-energy action illuminates topological aspects of heterotic-F-theory duality in 4D as well as in 6D. The existence of an F-theory realization also places geometrical constraints on the 4D supergravity theory in the large-volume limit.

Threads of Time

The concept of time’s arrow is examined using the principle of least action as given in its original non-Abelian form. When every entity of nature is considered to be composed of quantized actions, such an entity will change, either by absorbing quanta from surrounding actions or by emitting quanta to the surrounding actions. In natural processes, quanta disperse from high-energy density actions to low-energy density actions in quest of consuming free energy in least time. We propose that the flux of quanta embodies the flow of time, and therefore the irreversible consumption of free energy creates time’s arrow in a fundamental physical sense. The cosmological arrow of time results from universal processes that take place, most notably, in stars and other celestial systems, where matter, that is, bound actions, combusts to photons, that is, freely propagating actions. The biological arrow of time manifests itself in maturation processes where quanta absorb to emerging functional structures, leading eventually to aging processes where quanta, on balance, emit from disintegrating organs. Mathematical analysis of an evolutionary equation of motion, given in general terms of a spontaneous symmetry breaking process of actions, reveals the reason why future paths—and the future itself—remain inherently intractable.

Effect of the cosmological constant in the Hawking radiation of 3D charged dilaton black hole

This paper deals with the semiclassical radiation spectrum of static and circularly symmetric 3D charged dilaton black holes with cosmological constant {\Lambda} in non-asymptotically flat spacetimes. We first review the 3D charged dilaton black holes which are solution to low-energy string action. The wave equation of a massless scalar field is shown to be exactly solvable in terms of hypergeometric functions. Thus, the radiation spectrum and its corresponding temperature are obtained, precisely. Computations at high frequency regime show that the radiation spectrum yields the Hawking temperature of the black hole with no charge. Unlike the chargeless case, the Hawking temperature of the charged dilaton black holes is derived from the radiation spectrum at the low frequencies. The utmost importance of the {\Lambda} in the latter result is highlighted.

Testing dark matter warmness and quantity via the reduced relativistic gas model

We use the framework of a recently proposed model of reduced relativistic gas (RRG) to obtain the bounds for $\Omega$'s of Dark Matter and Dark Energy (in the present case, a cosmological constant), taking into consideration an arbitrary warmness of Dark Matter. An equivalent equation of state has been used by Sakharov to predict the oscillations in the matter power spectrum. Two kind of tests are accounted for in what follows, namely the ones coming from the dynamics of the conformal factor of the homogeneous and isotropic metric and also the ones based on linear cosmic perturbations. The RRG model demonstrated its high effectiveness, permitting to explore a large volume in the space of mentioned parameters in a rather economic way. Taking together the results of such tests as Supernova type Ia (Union2 sample), $H(z)$, CMB ($R$ factor), BAO and LSS (2dfGRS data), we confirm that $\La$CDM is the most favored model. At the same time, for the 2dfGRS data alone we found that an alternative model with a very small quantity of a Dark Matter is also viable. This output is potentially relevant in view of the fact that the LSS is the only test which can not be affected by the possible quantum contributions to the low-energy gravitational action.

Gravitational radiation in Hořava gravity

We study the radiation of gravitational waves by self-gravitating binary systems in the low-energy limit of Ho\ifmmode \check{r}\else \v{r}\fi{}ava gravity. We find that the predictions for the energy-loss formula of general relativity are modified already for Newtonian sources: the quadrupole contribution is altered, in part due to the different speed of propagation of the tensor modes; furthermore, there is a monopole contribution stemming from an extra scalar degree of freedom. A dipole contribution only appears at higher post-Newtonian order. We use these findings to constrain the low-energy action of Ho\ifmmode \check{r}\else \v{r}\fi{}ava gravity by comparing them with the radiation damping observed for binary pulsars. Even if this comparison is not completely appropriate---since compact objects cannot be described within the post-Newtonian approximation---it represents an order of magnitude estimate. In the limit where the post-Newtonian metric coincides with that of general relativity, our energy-loss formula provides the strongest constraints for Ho\ifmmode \check{r}\else \v{r}\fi{}ava gravity at low-energies.

On the Goldstino actions and their symmetries

Starting from the Akulov-Volkov (AV) action, we compute a finite-dimensional Lie group G of all field transformations of the form \lambda -> \lambda ' = \lambda + O(\lambda ^3) which preserve the functional structure of low-energy Goldstino-like actions. Associated with G is its twelve-parameter subgroup H of trivial symmetries of the AV action. The coset space G/H is naturally identified with the space of all Goldstino models. We then apply our construction to study the properties of five different Goldstino actions available in the literature. Making use of the most general field redefinition derived, we find explicit maps between all five cases. In each case there is a twelve- parameter freedom in these maps due to trivial symmetries inherent in the Goldstino actions. Finally, by using the pushforward of the AV supersymmetry, we find the off-shell nonlinear supersymmetry transformations of the other five actions and compare to those normally associated with these actions.

LOW ENERGY ACTION OF "COVARIANT" SUPERSTRING FIELD THEORY IN THE NS–NS pp-WAVE BACKGROUND

Exact construction of superstring field theory in some background fields is very important. We construct the low energy NS–NS sector of superstring field action in the pp-wave background with the flux of NS–NS antisymmetric tensor field (NS–NS pp-wave) without gauge fixing up to the second-order where the action is worldsheet BRST invariant. Here we use the word "covariant" in a invariant theory for a symmetric transformation of the pp-wave background which is not the Lorentz transformation in the flat background. Moreover, we prove the exact correspondence between this low energy action and the second-order perturbation of supergravity action in the same background. We also prove the correspondence of the gauge transformation in both the actions. This construction is based on the BRST first quantization of superstrings in the pp-wave background in our previous paper.

Unraveling Anharmonic Effects in the Vibrational Predissociation Spectra of H5O2+ and Its Deuterated Analogues

The nature of anharmonic couplings in the H(5)O(2)(+) "Zundel" ion and its deuterated isotopologues is investigated through comparison of their measured and calculated vibrational spectra. This follows a recent study in which we reported spectra for H(5)O(2)(+), D(5)O(2)(+), and D(4)HO(2)(+) from ∼600 to 4000 cm(-1), as well as H(4)DO(2)(+) in the OH and OD stretching regions [ J. Phys. Chem. B 2008 , 112 , 321 ]. While the assignments of the higher-energy transitions associated with the fundamentals of the exterior OH and OD motions are relatively straightforward, difficulties arise in the assignment of the lower-frequency regions that involve displacement of the bridging proton, especially for the isotopically mixed species. Here we revisit the Ar-tagged isotopomers, and report the low energy action spectrum of H(4)DO(2)(+) for the first time, as well as present significantly improved spectra for the D(4)HO(2)(+) and D(5)O(2)(+) systems. Band assignments are clarified in several cases using IR-IR hole-burning. We then investigate the physical origin of the anharmonic effects encoded in these spectra using a recently developed technique in which the anharmonic frequencies and intensities of transitions (involving up to two quanta of excitation) are evaluated using the ground state probability amplitudes [ J. Phys. Chem. A 2009 , 113 , 7346 ] obtained from diffusion Monte Carlo simulations. This approach has the advantage that it is applicable to low-symmetry systems [such as (HDO)H(+)(OH(2))] that are not readily addressed using highly accurate methods such as the multiconfigurational time-dependent Hartree (MCTDH) approach. Moreover, it naturally accommodates an intuitive evaluation of the types of motion that contribute oscillator strength in the various regions of the spectrum, even when the wave function is intrinsically not separable as a product of low-dimensional approximate solutions. Spectra for H(5)O(2)(+), D(5)O(2)(+), H(4)DO(2)(+), and D(4)HO(2)(+) that are calculated by this approach are shown to be in excellent agreement with the measured spectra for these species, leading to reassignments of two of the bands in the intramolecular bending region of D(4)HO(2)(+).

Dissipative phase fluctuations in superconducting wires capacitively coupled to diffusive metals

We study the screening of the Coulomb interaction in a quasi one-dimensional superconductor given by the presence of either a one- or a two-dimensional non-interacting electron gas. To that end, we derive an effective low-energy phase-only action, which amounts to treating the Coulomb and superconducting correlations in the random-phase approximation. We concentrate on the study of dissipation effects in the superconductor, induced by the effect of Coulomb coupling to the diffusive density-modes in the metal, and study its consequences on the static and dynamic conductivity. Our results point towards the importance of the dimensionality of the screening metal in the behavior of the superconducting plasma mode of the wire at low energies. In absence of topological defects, and when the screening is given by a one-dimensional electron gas, the superconducting plasma mode is completely damped in the limit $q\to 0$, and consequently superconductivity is lost in the wire. In contrast, we recover a Drude-response in the conductivity when the screening is provided by a two-dimensional electron gas.

Dual technicolor with hidden local symmetry

We consider a dual description of the technicolor-like gauge theory within the D4/D8 brane configuration with varying confinement and elecroweak symmetry breaking scales. Constructing an effective truncated model valid below a certain cut-off, we identify the particle spectrum with Kaluza-Klein modes of the model in a manner consistent with the hidden local symmetry. Integrating out heavy states, we find that the low-energy action receives nontrivial corrections stemming from the mixing between Standard Model and heavy gauge bosons which results in reduction of oblique parameters.

Four dimensional string solutions in Hořava-Lifshitz gravity

We investigate string-like solutions in four dimensions based on Hořava-Lifshitz gravity. For a restricted class of solutions where the Cotton tensor vanishes, we find that the string-like solutions in Einstein gravity including the BTZ black strings are solutions in Hořava-Lifshitz gravity as well. The geometry is warped in the same way as in Einstein gravity, but the “conformal” lapse function is not constrained in Hořava-Lifshitz gravity. It turns out that if λ ≠ 1, there exist no other solutions. For the value of model parameter with which Einstein gravity recovers in IR limit (i.e., λ = 1), there exists an additional solution of which the conformal lapse function is determined. Interestingly, this solution admits a uniform BTZ black string along the string direction, which is distinguished from the warped BTZ black string in Einstein gravity. We also point out that this solution is exactly the same with the black string solution obtained in a low-energy string theory action including the dilaton and the Kalb-Ramond fields.

Metastable States and Macroscopic Quantum Tunneling in a Cold-Atom Josephson Ring

We study macroscopic properties of a system of weakly interacting neutral bosons confined in a ring-shaped potential with a Josephson junction. We derive an effective low energy action for this system and evaluate its properties. In particular, we find that the system possesses a set of metastable current-carrying states and evaluate the rates of transitions between these states due to macroscopic quantum tunneling and thermal activation mechanism. Finally, we discuss signatures of different metastable states in the time-of-flight images and argue that the effect is observable within currently available experimental technique.

Algebraic geometry approach in gravity theory and new relations between the parameters in type I low-energy string theory action in theories with extra dimensions

On the base of the distinction between covariant and contravariant metric tensor components, a new (multivariable) cubic algebraic equation for reparametrization invariance of the gravitational Lagrangian has been derived and parametrized with complicated non - elliptic functions, depending on the (elliptic) Weierstrass function and its derivative. This is different from standard algebraic geometry, where only two-dimensional cubic equations are parametrized with elliptic functions and not multivariable ones. Physical applications of the approach have been considered in reference to theories with extra dimensions. The s.c. "length function" l(x) has been introduced and found as a solution of quasilinear differential equations in partial derivatives for two different cases of "compactification + rescaling" and "rescaling + compactification". New physically important relations (inequalities) between the parameters in the action are established, which cannot be derived in the case $l=1$ of the standard gravitational theory, but should be fulfilled also for that case.

Towards a solution of the strongCPproblem by compact extra dimensions

We propose a way towards a dynamical solution of the strong $CP$ in models with compact extra dimensions. To this aim we consider a one dimensional toy model for QCD, which contains a vacuum angle and a strong $CP$-like problem. We further consider a higher dimensional theory, which has a trivial vacuum structure and which reproduces the perturbative properties of the toy model in the low-energy limit. In the weak coupling regime, where our computations are valid, we show that the vacuum structure of the low-energy action is still trivial and the strong $CP$ problem does not arise. Also, no axionlike particles are generated in this setup.