arXiv subjects

Holger B. Nielsen

Publications and source records attributed to Holger B. Nielsen.

At least 37 records · Page 2Linked to original sources

arXiv2007

Dirac Sea and Hole Theory for Bosons II -- Renormalization Approach --

In bosonic formulation of the negative energy sea, so called Dirac sea presented in the preceding paper [arXiv:hep-th/0603242], one of the crucial points is how to construct a positive definite inner product in the negative energy states, since naive attempts would lead to non-positive definite ones. In the preceding paper the non-local method is used to define the positive definite inner product. In the present article we make use of a kind of $ε$-regularization and renormalization method which may clarify transparently the analytical properties of our formulation.

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arXiv2007

Degenerate vacua from unification of second law of thermodynamics with other laws

Using our recent attempt to formulate second law of thermodynamics in a general way into a language with a probability density function, we derive degenerate vacua. Under the assumption that many coupling constants are effectively ``dynamical'' in the sense that they are or can be counted as initial state conditions, we argue in our model behind the second law that these coupling constants will adjust to make several vacua all having their separate effective cosmological constants or, what is the same, energy densities, being almost the \underline{same} value, essentially zero. Such degeneracy of vacuum energy densities is what one of us works on a lot under the name "The multiple point principle" (MPP).

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arXiv2006

Non-existence of Irreversible Processes in Compact Space Time

It is shown that if physical space time were truly compact there would only be of the order of one solutions to the classical field equations with a weighting to be explained. But that would not allow any peculiar choice of initial conditions that could support a non-trivial second law of thermodynamics. We present a no-go theorem: Irreversible processes would be extremely unlikely to occur, for the almost unique solution for the intrinsically compact space time world, although irreversible processes are well known to occur in general.What we here assume -- compact space time -- excludes that universe could exist eternally.

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arXiv2006

Entropy Currents for Reversible Processes in a System of Differential equations. -- The Case of Latticized Classical Field Theory --

We consider a very complicated system of some latticized differential equations that is considered as equations of motion for a field theory. We define macro state restrictions for such a system analogous to thermodynamical states of a system in statistical mechanics. For the case in which we have assumed adiabaticity in a generalized way which is equivalent to reversible processes. It is shown that we can define various entropy currents, not only one. It is indeed surprising that, for a two dimensional example of lattice field theory, we get three different entropy currents, all conserved under the adiabaticity condition.

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arXiv2006

Future Dependent Initial Conditions from Imaginary Part in Lagrangian

We want to unify usual equation of motion laws of nature with "laws" about initial conditions, second law of thermodynamics, cosmology. By introducing an imaginary part -- of a similar form but different parameters as the usual real part -- for the action to be used in the Feynmann path way integral we obtain a model determining (not only equations of motion but) also the initial conditions, for say a quantum field theory. We set up the formalism for e.g. expectation values, classical approximation in such a model and show that provided the imaginary part gets unimportant except in the Big Bang era the model can match the usual theory. Speculatively requiring that there be place for Dirac strings and thus in principle monopoles in the model we can push away the effects of the imaginary part to be involved only with particles not yet found. Most promising for seeing the initial condition determining effects from the imaginary part is thus the Higgs particle. We predict that the width of the Higgs particle shall likely turn out to be (appreciably perhaps) broader than calculated by summing usual decay rates. Higgs machines will be hit by bad luck.

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arXiv2006

Law Behind Second Law of Thermodynamics --Unification with Cosmology--

In an abstract setting of a general classical mechanical system as a model for the universe we set up a general formalism for a law behind the second law of thermodynamics, i.e. really for "initial conditions". We propose a unification with the other laws by requiring similar symmetry and locality properties.

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arXiv2006

Compactified Time and likely Entropy -- World Inside Time Machine: Closed Time-like Curve --

If a macroscopic (random) classical system is put into a random state in phase space, it will of course the most likely have an almost maximal entropy according to second law of thermodynamics. We will show, however, the following theorem: If it is enforced to be periodic with a given period $T$ in advance, the distribution of the entropy for the otherwise random state will be much more smoothed out, and the entropy could be very likely much smaller than the maximal one. Even quantum mechanically we can understand that such a lower than maximal entropy is likely. A corollary turns out to be that the entropy in such closed time-like loop worlds remain constant.

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arXiv2006

Intrinsic Periodicity of Time and Non-maximal Entropy of Universe

The universe is certainly not yet in total thermodynamical equilibrium,so clearly some law telling about special initial conditions is needed. A universe or a system imposed to behave periodically gets thereby required ``initial conditions". Those initial conditions will \underline{not} look like having already suffered the heat death, i.e. obtained the maximal entropy, like a random state. The intrinsic periodicity explains successfully why entropy is not maximal, but fails phenomenologically by leading to a \underline{constant}entropy.

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arXiv2005

Unification of Cosmology and Second Law of Thermodynamics: Solving Cosmological Constant Problem, and Inflation

We seek here to unify the second law of thermodynamics with the other laws, or at least to put up a law behind the second law of thermodynamics. Assuming no fine tuning, concretely by a random Hamiltonian, we argue just from equations of motion -- but {\em without} second law -- that entropy cannot go first up and then down again except with the rather strict restriction S_{large} \le S_{small 1} + S_{small 2}. Here S_{large} is the "large" entropy in the middle era while S_{small 1} and S_{small 2} are the entropies at certain times before and after the S_{large} - era respectively. From this theorem of "no strong maximum for the entropy" a cyclic time S^1 model world could have entropy at the most varying by a factor two and would not be phenomenologically realistic. With an open ended time axis (-\infty, \infty) ={\bf R} some law behind the second law of thermodynamics is needed if we do not obtain as the most likely happening that the entropy is maximal (i.e. the heat death having already occurred from the start). We express such a law behind the second law -- or unification of second law with the other ones -- by assigning a probability weight $P$ for finding the world/the system in various places in phase space. In such a model $P$ is almost unified with the rest as P = exp (-2 ~S_{Im}) with S_{Im} going in as the imaginary part of the action. We derive quite naturally the second law for practical purposes, a Big Bang with two sided time directions and a need for a bottom in the Hamiltonian density. Assuming the cosmological constant is a dynamical variable in the sense that it is counted as "initial condition" we even solve in our model the cosmological constant problem \underline{without} any allusion to anthropic principle.

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arXiv2005

Supersymmetric Relativistic Quantum Mechanics

We present an attempt to formulate the supersymmetric and relativistic quantum mechanics in the sense of realizing supersymmetry on the single particle level, by utilizing the equations of motion which is equivalent to the ordinary 2nd quantization of the chiral multiplet. The matrix formulation is used to express the operators such as supersymmtry generators and fields of the chiral multiplets. We realize supersymmetry prior to filling the Dirac sea.

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arXiv2005

Dirac Sea for Bosons also and SUSY for Single Particles

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arXiv2005

Hole Theory of Boson Sea

We propose a hole theory for bosons, in which, analogous to fermions, a hole produced by the annihilation of one negative energy boson is an anti-particle. We show that the boson vacuum indeed also consists of a sea in which all negative energy states are filled and the density of probability of the Klein-Gordon theory is positive definite also for the negative energy solution. This formalism is obtained by introducing the notion of a double harmonic oscillator, which is constructed by extending the condition imposed on the wave function. This double harmonic oscillator contains not only positive energy states but also negative energy ones. The physical result obtained from our method is consistent with that of the ordinary second quantization formalism. Our formulation is also consistent with the supersymmetric point of view. We finally suggest applications of our method to the anomalies of boson theories and the string theories.

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arXiv2005

Negative Energy (Dirac-like) Sea for Bosons and Supersymmetry

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arXiv2004

Dirac Sea for Bosons I -- Formulation of Negative Energy Sea for Bosons

It is proposed to make formulation of second quantizing a bosonic theory by generalizing the method of filling the Dirac negative energy sea for fermions. We interpret that the correct vacuum for the bosonic theory is obtained by adding minus one boson to each single particle negative energy states while the positive energy states are empty. The boson states are divided into two sectors ; the usual positive sector with positive and zero numbers of bosons and the negative sector with negative numbers of bosons. Once it comes into the negative sector it cannot return to the usual positive sector by ordinary interaction due to a barrier. It is suggested to use as a playground model in which the filling of empty fermion Dirac sea and the removal of boson from the negative energy states are not yet performed. We put forward such a naive vacuum world in the present paper. The successive paper will concern a CPT-like Theorem in the naive vacuum world.

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arXiv2004

Dirac Sea for Bosons II -- Study of the Naive Vacuum Theory for the Playground World Prior to Filling the Negative Energy Sea --

We use our previous idea, in which at first we perform a naive second quantization of both negative and positive energy for the Klein-Gordon equation analogous to the unfilled Dirac sea for fermions, to study as a playground this naive second quantization theory. It is not to be taken seriously physically in as far as it has indefinite Fock space, but it has nevertheless interesting possibilities: Although the naive (quantization) theory represents a spontaneous breakdown of the usual CPT-symmetry, we shall show that it obeys a certain replacement for the CPT-theorem for which a proof is presented in detail.

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arXiv2004

Boson Sea versus Dirac Sea -- General formulation of boson sea through supersymmetry --

We consider the long standing problem in field theories of bosons that the boson vacuum does not consist of a `sea', unlike the fermion vacuum. We show with the help of supersymmetry considerations that the boson vacuum indeed does also consist of a sea in which the negative energy states are all "filled", analogous to the Dirac sea of the fermion vacuum, and that a hole produced by the annihilation of one negative energy boson is an anti-particle. Here, we must admit that it is only possible if we allow --as occurs in the usual formalism anyway-- that the "Hilbert space" for the single particle bosons is not positive definite. This might be formally coped with by introducing the notion of a double harmonic oscillator, which is obtained by extending the condition imposed on the wave function. This double harmonic oscillator includes not only positive energy states but also negative energy states. We utilize this method to construct a general formalism for a boson sea analogous to the Dirac sea, irrespective of the existence of supersymmetry. The physical result is consistent with that of the ordinary second quantization formalism. We finally suggest applications of our method to the string theories.

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arXiv2001

A New Type of String Field Theory

We propose a new way of second quantizing string theory. The method is based on considering the Fock space of strings described by constituents which make up the $X^μ_R$ and the $X^μ_L$ i.e. the right and left mover modes separately. A state with any number of strings get represented by the Cartesian product of two free particle Fock spaces, one for right mover degrees of freedom, and one for left. The resulting string field theory is a free theory.

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arXiv1998

Dirac Sea for Bosons

It is proposed to make formulation of second quantizing a bosonic theory by generalizing the method of filling the Dirac negative energy sea for fermions. We interpret that the correct vacuum for the bosonic theory is obtained by adding minus one boson to each single particle negative energy states while the positive energy states are empty. The boson states are divided into two sectors ; the usual positive sector with positive and zero numbers of bosons and the negative sector with negative numbers of bosons. Once it comes into the negative sector it cannot return to the usual positive sector by ordinary interaction due to a barrier. It is suggested to use as a playround models in which the filling of empty fermion Dirac sea and the removal of boson from the negative energy states are not yet performed. We put forward such a naive vacuum world and propose a CPT-like theorem for it.We study it in detail and give a proof for $λ/4 (ϕ^+ϕ)^2$ theory. The CPT-like theorem is a strong reflection, but does not include inversion of operator order which is involved in the ordinary CPT theorem. Instead it needs certain analytic continuation of the multiple wave function when the state is formulated as a finite number of particles present.

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