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Holger Bech Nielsen

Publications and source records attributed to Holger Bech Nielsen.

At least 55 records · Page 3Linked to original sources

Influence from Future, Arguments

It is the purpose of the present article to collect arguments for, that there should exist in fact -- although not necessarily yet found -- some law, which imply an adjustment to special features to occur in the future. In our own "complex action model" we suggest a version in which the "goal" according to which the future is being arranged is to diminish the integral over time and space of the numerical square of the Higgs field. We end by suggesting that optimistically calculated the collected evidences by coincidences runs to that the chance for getting so good agreement by accident would be of the order of only 1 in 30000. In addition we review that the cosmological constant being so small can be considered evidence for some influence backward in time. Anthropic principle may be considered a way of simulating influence backward in time.

physics.gen-ph↗

Deriving diffeomorphism symmetry

In an earlier article, we have "derived" space, as a part of the Random Dynamics project. In order to get locality we need to obtain reparametrization symmetry, or equivalently, diffeomorphism symmetry. There we sketched a procedure for how to get locality by first obtaining reparametrization symmetry, or equivalently, diffeomorphism symmetry. This is the object of the present article.

gr-qc↗

Seeking a Game in which the standard model Group shall Win

It is attempted to construct a group-dependent quantity that could be used to single out the Standard Model group S(U(2) x U(3)) as being the "winner" by this quantity being the biggest possible for just the Standard Model group. The suggested quantity is first of all based on the inverse quadratic Cassimir for the fundamental or better smallest faithful representation in a notation in which the adjoint representation quadratic Cassimir is normalized to unity. Then a further correction is added to help the wanted Standard Model group to win and the rule comes even to involve the Abelian group U(1) to be multiplied into the group to get this correction be allowed. The scheme is suggestively explained to have some physical interpretation(s). By some appropriate proceedure for extending the group dependent quantity to groups that are not simple we find a way to make the Standard Model Group the absolute "winner". Thus we provide an indication for what could be the reason for the Standard Model Group having been chosen to be the realized one by Nature.

hep-ph↗

PREdicted the Higgs Mass

We like to investigate the idea of taking as non-accidental a remarkably good agreement of our (C.D. Froggatt and myself, and also with Yasutaka Takanishi) prediction of the Higgs mass. Our modernized most simple "multiple point principle" prediction $129.4 \pm 2$ GeV versus the recently observed $126 \pm 1$ GeV agrees well. The PREdicted Higgs mass is essentially the smallest value, that would not make our present vacuum unstable. There are two slightly different versions in as far as we can either use absolute stability by the alternative vacuum being required to have higher energy density than the present one or just metastability requiring that our vacuum should not have decayed in the early time just after big bang (or later if that should be easier). This is of course provided we suppose that the Standard Model would function almost all the way up to the scale relevant for the alternative vacuum (which as we shall see is close to the Planck energy scale for the Higgs field expectation value). The principle we used to our PREdiction were the requirement of degenerate vacua which we called "multiple point principle" and I shall seek to deliver some arguments that this MPP is "nice" to assume, i.e. it is likely to be true.

hep-ph↗

Correspondence between future-included and future-not-included theories

We briefly review the correspondence principle proposed in our previous paper, which claims that if we regard a matrix element defined in terms of the future state at time $T_B$ and the past state at time $T_A$ as an expectation value in the complex action theory whose path runs over not only past but also future, the expectation value at the present time $t$ of a future-included theory for large $T_B-t$ and large $t-T_A$ corresponds to that of a future-not-included theory with a proper inner product for large $t-T_A$. This correspondence principle suggests that the future-included theory is not excluded phenomenologically.

quant-ph↗

Formulation of Complex Action Theory

We formulate a complex action theory which includes operators of coordinate and momentum $\hat{q}$ and $\hat{p}$ being replaced with non-hermitian operators $\hat{q}_{new}$ and $\hat{p}_{new}$, and their eigenstates ${}_m <_{new} q |$ and ${}_m <_{new} p |$ with complex eigenvalues $q$ and $p$. Introducing a philosophy of keeping the analyticity in path integration variables, we define a modified set of complex conjugate, real and imaginary parts, hermitian conjugates and bras, and explicitly construct $\hat{q}_{new}$, $\hat{p}_{new}$, ${}_m <_{new} q |$ and ${}_m <_{new} p |$ by formally squeezing coherent states. We also pose a theorem on the relation between functions on the phase space and the corresponding operators. Only in our formalism can we describe a complex action theory or a real action theory with complex saddle points in the tunneling effect etc. in terms of bras and kets in the functional integral. Furthermore, in a system with a non-hermitian diagonalizable bounded Hamiltonian, we show that the mechanism to obtain a hermitian Hamiltonian after a long time development proposed in our letter works also in the complex coordinate formalism. If the hermitian Hamiltonian is given in a local form, a conserved probability current density can be constructed with two kinds of wave functions.

quant-ph↗

Complex Action Support from Coincidences of Couplings

Our model \cite{ownmMPP}\cite{SIMPP} with complex action in a functional integral formulation with path integrals extending over all times, past and future, is reviewed. Several numerical relations between coupling constants are presented as supporting evidence. The new evidence is that some more unexplained coincidences are explained in our model: 1) The "scale problem" is solved because the Higgs field expectation value is predicted to be very small compared to say some fundamental scale, that might be the Planck scale. 2) The Higgs VEV need not, however, to be just zero, but rather is predicted to be so that the running top-Yukawa coupling just is about to be unity at this scale; in this way the (weak) scale easily becomes "exponentially small". Instead of the top-Yukawa we should rather say the highest flavour Yukawa coupling here. These predictions are only achieved by allowing the principle of minimization of the imaginary part of the action SI(history) to to a certain extent adjust some coupling constants in addition to the initial conditions. If Susy-partners are not found in LHC, it would strengthen the need for "solution" of the hierarchy or rather scale problem along the lines of the present article.

hep-ph↗

Remarkable Relation from Minimal Imaginary Action Model

If it is to be true that the history of the universe should be adjusted to minimize the "imaginary part of action" [arXiv:0802.2991, arXiv:0711.3080, arXiv:0707.1919, arXiv:hep-ph/0612032, arXiv:hep-th/0509205, arXiv:hep-th/0701018], it would be "easiest" to have this "imaginary part of the action" to be rather independent of whether the neutrons are converted to electrons and protons (and neutrinos), and therefore of whether the contribution to the imaginary part of the Lagrangian were conserved under this conversion. Under the further assumption - which is reasonable - that the by far dominant term in the imaginary part of the Lagrangian density is the one corresponding to the Higgs mass square term in the Standard Model Lagrangian density mH**2 |phi(x)|**2 we derive a relation: (down mass square minus up mass square) = constituent quark mass times electron mass/"ln", where "ln" is defined by <1/gamma >= "ln"/ < gamma > and is of the order of 1 to 4, where gamma stands for relativity gamma of a valence quark inside a nucleon. This relation is very well satisfied with the phenomeno- logically estimated current algebra quark masses mu, md, and the constituent mass mconstituent for the light quarks, taken say to be one third of the nucleon mass. Our model has been criticised on the ground that it should have prevented cosmic rays with energies capable of producing Higgs particles, when hitting say the atmosphere. Indeed there is, however, a well known "knee" in the density curve as function of energy at an order of magnitude for the cosmic ray particle energy close to the effective threshold for Higgs production. A parameter giving the order of magnitude of number of Higgsses to be produced in order to get a significant effect is estimated to be about 300000.

physics.gen-ph↗

Automatic Hermiticity

We study a diagonalizable Hamiltonian that is not at first hermitian. Requirement that a measurement shall not change one Hamiltonian eigenstate into another one with a different eigenvalue imposes that an inner product must be defined so as to make the Hamiltonian normal with regard to it. After a long time development with the non-hermitian Hamiltonian, only a subspace of possible states will effectively survive. On this subspace the effect of the anti-hermitian part of the Hamiltonian is suppressed, and the Hamiltonian becomes hermitian. Thus hermiticity emerges automatically, and we have no reason to maintain that at the fundamental level the Hamiltonian should be hermitian. If the Hamiltonian is given in a local form, a conserved probability current density can be constructed with two kinds of wave functions. We also point out a possible misestimation of a past state by extrapolating back in time with the hermitian Hamiltonian. It is a seeming past state, not a true one.

quant-ph↗

The Cheshire Cat Principle from Holography

The Cheshire cat principle states that hadronic observables at low energy do not distinguish between hard (quark) or soft (meson) constituents. As a result, the delineation between hard/soft (bag radius) is like the Cheshire cat smile in Alice in wonderland. This principle reemerges from current holographic descriptions of chiral baryons whereby the smile appears in the holographic direction. We illustrate this point for the baryonic form factor.

hep-th↗

Particular boundary condition ensures that a fermion in d=1+5, compactified on a finite disk, manifests in d=1+3 as massless spinor with a charge 1/2, mass protected and chirally coupled to the gauge field

The genuine Kaluza-Klein-like theories--with no fields in addition to gravity--have difficulties with the existence of massless spinors after the compactification of some space dimensions \cite{witten}. We proposed in previous paper a boundary condition for spinors in d=(1+5) compactified on a flat disk that ensures masslessness of spinors (with all positive half integer charges) in d=(1+3) as well as their chiral coupling to the corresponding background gauge gravitational field. In this paper we study the same toy model, proposing a boundary condition allowing a massless spinor of one handedness and only one charge (1/2) and infinitely many massive spinors of the same charge, allowing disc to be curved. We define the operator of momentum to be Hermitean on the vector space of spinor states--the solutions on a disc with the boundary.

hep-th↗

Fermions with no fundamental charges call for extra dimensions

We call attention to that if assuming no conserved charges in the fundamental theory with fermions, which carry only a spin and interact with only the gravity, the dimensions $4, 12, 20,.....,$ as well as all odd dimensions, are excluded under the requirement of mass protection. If more than one family is required, than only dimensions d=2 (mod 4) remains as acceptable, since then other by 4 devisable dimensions are excluded.

hep-th↗

Implementation of the Multiple Point Principle in the Two-Higgs Doublet Model of type II

The multiple point principle (MPP) is applied to the non--supersymmetric two-Higgs doublet extension of the Standard Model (SM). The existence of a large set of degenerate vacua at some high energy scale caused by the MPP results in a few relations between Higgs self-coupling constants which can be examined at future colliders. The numerical analysis reveals that these MPP conditions constrain the mass of the SM--like Higgs boson to lie below 180 GeV for a wide set of MPP scales $Λ$ and $\tanβ$.

hep-ph↗

Spins and charges in Grassmann space and Kahler spinors in space of differential forms

One of us got spins and charges of not only scalars and vectors but also of spinors out of fields, which are antisymmetric tensor fields. Kahler got spins of spinors out of differential forms, which again are antisymmetric tensor fields. Using our simple Grassmann formulation of spins and charges of either spinors or vectors and comparing it to the Dirac-Kahler formulation of spinors, we generalize the Dirac-Kahler approach to vector internal degrees of freedom and to charges of either spinors or vectors and tenzors and point out how at all spinors can appear in both approaches.

hep-th↗

What comes beyond the standard model?

The Proceedings collects the results of ten days of discussions on the open questions of the Standard electroweak model as well as the review of the introductory talks, connected with the discussions.

hep-ph↗

Chaos, Scaling and Existence of a Continuum Limit in Classical Non-Abelian Lattice Gauge Theory

We discuss space-time chaos and scaling properties for classical non-Abelian gauge fields discretized on a spatial lattice. We emphasize that there is a ``no go'' for simulating the original continuum classical gauge fields over a long time span since there is a never ending dynamical cascading towards the ultraviolet. We note that the temporal chaotic properties of the original continuum gauge fields and the lattice gauge system have entirely different scaling properties thereby emphasizing that they are entirely different dynamical systems which have only very little in common. Considered as a statistical system in its own right the lattice gauge system in a situation where it has reached equilibrium comes closest to what could be termed a ``continuum limit'' in the limit of very small energies (weak non-linearities). We discuss the lattice system both in the limit for small energies and in the limit of high energies where we show that there is a saturation of the temporal chaos as a pure lattice artifact. Our discussion focuses not only on the temporal correlations but to a large extent also on the spatial correlations in the lattice system. We argue that various conclusions of physics have been based on monitoring the non-Abelian lattice system in regimes where the fields are correlated over few lattice units only. This is further evidenced by comparison with results for Abelian lattice gauge theory. How the real time simulations of the classical lattice gauge theory may reach contact with the real time evolution of (semi-classical aspects of) the quantum gauge theory (e.g. Q.C.D.) is left as an important question to be further examined.

hep-th↗

A ${\bf Z}_2$ Classification for 2D Fermion Level Crossing

We demonstrate that the number of fermionic zero modes of the static $2$-dimensional Dirac operator in the background of $SU(2)$ static gauge-Higgs field configurations is a topological invariant modulo four. Static configurations which are everywhere odd under parity with even-parity pure gauge behaviour at infinity admit $4n$, $n\in {\bf Z},$ zero modes of the Jackiw-Rebbi (JR) type. Odd-parity configurations with odd-parity pure gauge behaviour at infinity are topologically disconnected from the vacuum and admit $4 n + 2$ fermionic zero energy solutions. The classification implies the collapse of half of the fermion zero modes upon embedding a $2$-dimensional gauge-Higgs configuration (string) with odd-parity pure gauge behaviour at infinity into the $3$-dimensional Minkowski space.

hep-ph↗