Change search
Refine search result
12 1 - 50 of 74
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Anoushirvani, B.
    et al.
    Enström, Daniel
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Ökvist, P.
    Nicolaidis, A.
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    Gamma-ray bursts from primordial quark objects in space1997In: Proceedings of the Joint Meeting of the Networks 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997, 1997Conference paper (Refereed)
    Abstract [en]

    We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.

  • 2.
    Anselmino, M.
    et al.
    Dipertemento di Fisica Teoria, Universita di Torino and INFS.
    Boglione, M.
    Department of Physics and Astronomy, Vrije Universitet Amsterdam.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Murgia, F.
    Institute Nazionale Fisica Nucleare, Seizone di Cagliari.
    Predictions for single spin asymmetries in ℓ parrow -> π X and γ * parrow -> π X2000In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 13, no 3, p. 519-526Article in journal (Refereed)
    Abstract [en]

    Predictions for the single transverse spin asymmetry AN in semi-inclusive DIS processes are given; non-negligible values of AN may arise from spin effects in the fragmentation of a polarized quark into a final hadron with a transverse momentum ěc k⊥ with respect to the jet axis, the so-called Collins effect. The elementary single spin asymmetry of the fragmenting quark has been fixed in a previous paper, by fitting data on parrow p -> π X, and by assuming that the QCD factorization theorem holds also when transverse momenta are taken into account. The predictions given here are based on the assumption that the Collins effect is the only cause of the observed single spin asymmetries in parrow p -> π X. Eventual spin and ěc k⊥ dependences in the quark distribution functions, the so-called Sivers effect, are also discussed.

  • 3. Anselmino, M.
    et al.
    Boglione, Mariaelena
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Burgia, F.
    Inclusive production of hadrons in lepton (polarized) p (polarized) ---> h (polarized) X and spin measurements1996In: Proceedings of International Workshop on Deep Inelastic Scattering and Related Phenomena, DIS 96, 1996, p. 583-589Conference paper (Refereed)
    Abstract [en]

    We discuss the production of polarized hadrons in polarized lepton nucleon interactions and show that the helicity density matrix of the hadron, when measurable, can give information on the spin structure of the nucleon and the spin dependence of the quark fragmentation process. Single spin asymmetries in the $\ell N^\uparrow \to hX$ process are also briefly discussed.

  • 4. Anselmino, M.
    et al.
    Boglione, Mariaelena
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Murgia, F.
    Spin measurements in l p ---> h X deep inelastic scattering1997In: SPIN 96: proceedings; September 10-14, 1996, Amsterdam, the Netherlands, Singapore: World Scientific Publishing Co Pte Ltd , 1997, p. 346-348Conference paper (Refereed)
    Abstract [en]

    The production of hadrons in polarized lepton-nucleon deep inelastic scattering is discussed. The helicity density matrix of the hadron is computed within the QCD hard scattering formalism and its elements are shown to yield information on the spin structure of the nucleon and the spin dependence of the quark fragmentation process. The case of $\rho$ vector mesons is considered in more detail and estimates are given.

  • 5.
    Anselmino, Mauro
    et al.
    Dipartimento di Fisica Teorica, Università di Torino and Istituto Nazionale di Fisica Nucleare, Sezione di Torino.
    Boglione, Maria
    Dipartimento di Fisica Teorica, Università di Torino and Istituto Nazionale di Fisica Nucleare, Sezione di Torino.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Murgia, Francesco
    Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari.
    Polarized inclusive leptoproduction, lN→hX, and the hadron helicity density matrix ρ(h): Possible measurements and predictions1996In: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 54, no 1, p. 828-837Article in journal (Refereed)
    Abstract [en]

    We discuss the production of hadrons in polarized lepton-nucleon interactions and in the current jet fragmentation region; using the QCD hard scattering formalism we compute the helicity density matrix of the hadron and show how its elements, when measurable, can give information on the spin structure of the nucleon and the spin dependence of the quark fragmentation process. The cases of ρ vector mesons and Λ baryons are considered in more detail and, within simplifying assumptions, some estimates are given

  • 6.
    Dugne, Jean-Jacques
    et al.
    Laboratoire de Physique Corpusculaire, Université Blaise Pascal Clermont-Ferrand.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Preon trinity: a schematic model of leptons, quarks and heavy vector bosons2002In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 60, no 2, p. 188-194Article in journal (Refereed)
    Abstract [en]

    Quarks, leptons and heavy vector bosons are suggested to be composed of stable spin- (1/2) preons, existing in three flavours, combined according to simple rules. Straightforward consequences of an SU(3) preon-flavour symmetry are the conservation of three lepton numbers, oscillations and decays between some neutrinos, and the mixing of the d and s quarks, as well as of the vector fields W0 and B0. We find a relation between the Cabibbo and Weinberg mixing angles, and predict new (heavy) leptons, quarks and vector bosons, some of which might be observable at the Fermilab Tevatron and the future CERN LHC. A heavy neutrino might even be visible in existing data from the CERN LEP facility.

  • 7. Dugne, Jean-Jacques
    et al.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Predazzi, Enrico
    Higgs pain? Take a preon!1997In: Proceedings of the Meeting on 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997, 1997Conference paper (Refereed)
    Abstract [en]

    The Higgs mechanism is the favourite cure for the main problem with electroweak unification, namely how to reconcile a gauge theory with the need for massive gauge bosons. This problem does not exist in preon models for quark and lepton substructure with composite $Z^0$ and $W$s, which, consequently, also avoid all other theoretical complications and paradoxes with the Higgs mechanism. We present a new, minimal preon model, which explains the family structure, and predicts several new, heavy quarks, leptons and vector bosons. Our preons obey a phenomenological supersymmetry, but without so-called squarks and sleptons, since this SUSY is effective only on the composite scale.

  • 8. Dugne, Jean-Jacques
    et al.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Predazzi, Enrico
    Preon Trinity: a new model of leptons and quarks1999In: Beyond the desert 1999: accelerator, non-accelerator, and space approaches into the next millennium ; proceedings of the Second International Conference on Particle Physics Beyond the Standard Model, Castle Ringberg, Germany, 6 - 12 June 1999 / [ed] Hans Volker Klapdor-Kleingrothaus, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 1999Conference paper (Refereed)
    Abstract [en]

    A new model for the substructure of quarks, leptons and weak gauge bosons, is discussed. It is based on three fundamental and absolutely stable spin-1/2 preons. Its preon flavour SU(3) symmetry leads to a prediction of nine quarks, nine leptons and nine heavy vector bosons. One of the quarks has charge $-4e/3$, and is speculated to be the top quark (whose charge has not been measured). The flavour symmetry leads to three conserved lepton numbers in all known weak processes, except for some neutrinos, which might either oscillate or decay. There is also a (Cabibbo) mixing of the $d$ and $s$ quarks due to an internal preon-antipreon annihilation channel. An identical channel exists inside the composite $Z^0$, leading to a relation between the Cabibbo and Weinberg mixing angles.

  • 9. Dugne, Jena-Jacques
    et al.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Predazzi, Enrico
    Preon trinity1998Report (Other academic)
    Abstract [en]

    We present a new minimal model for the substructure of all known quarks, leptons and weak gauge bosons, based on only three fundamental and stable spin-1/2 preons. As a consequence, we predict three new quarks, three new leptons, and six new vector bosons. One of the new quarks has charge $-4e/3$. The model explains the apparent conservation of three lepton numbers, as well as the so-called Cabibbo-mixing of the $d$ and $s$ quarks, and predicts electromagnetic decays or oscillations between the neutrinos $\bar{\nu}_{\mu}$ ($\nu_{\mu}$) and $\nu_e$ ($\bar{\nu}_e$). Other neutrino oscillations, as well as rarer quark mixings and CP violation can come about due to a small quantum-mechanical mixing of two of the preons in the quark and lepton wave functions.

  • 10. Enström, Daniel
    et al.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Luminosities of high-redshift objects in an accelerating universe1999Report (Other academic)
    Abstract [en]

    The results from the Supernova Cosmology Project indicate a relation between cosmic distance and redshift that corresponds to an accelerating Universe, and, as a consequence, the presence of an energy component with negative pressure. This necessitates a re-evaluation of such astrophysical luminosities that have been derived through conventional redshift analyses of, e.g., gamma-ray bursts and quasars. We have calculated corrected luminosity distances within two scenarios; the standard one with a non-zero cosmological constant, and the more recently proposed ``quintessence'', with a slowly evolving energy-density component. We find luminosity corrections from +30 to -40 per cent for redshifts with $z=0 - 10$. This finding implicates that the SCP data do not, by themselves, require a revision of the current, rather qualitative modeling of gamma-ray bursts and quasar properties.

  • 11. Enström, Daniel
    et al.
    Fredriksson, Sverker
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nicolaidis, A.
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    A Quark matter dominated universe1998Report (Other academic)
    Abstract [en]

    We present a new scenario for the development of the Universe after the Big Bang, built on the conjecture that a vast majority of the primordial quark matter did not undergo a phase transition to normal nuclear matter, but rather split up into massive quark objects that remained stable. Hence, such primordial quark matter would make up the so-called dark matter. We discuss, mostly in qualitative terms, the consequences for galaxy formation, the origin of normal matter, the occurrence of massive black-holes in galactic centres and the cosmic gamma-ray bursts.

  • 12. Enström, Daniel
    et al.
    Fredriksson, Sverker
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nicolaidis, A.
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    Gamma-Ray Bursts and Dark Matter: a joint origin?1998Conference paper (Refereed)
  • 13. Fredriksson, Sverker
    et al.
    Enström, Daniel
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    Nicolaidis, A.
    Is dark matter made up of massive quark objects?1999In: Dark matter in astrophysics and particle physics 1998: proceedings of the Second International Conference on Dark Matter in Astrophysics and Particle Physics / [ed] Hans Volker Klapdor-Kleingrothaus ; L. Baudis, Bristol: IOP Publishing Ltd , 1999, p. 651-658Conference paper (Refereed)
    Abstract [en]

    We suggest that dark matter is made up of massive quark objects that have survived from the Big Bang, representing the ground state of "baryonic'' matter. Hence, there was no overall phase transition of the original quark matter, but only a split-up into smaller objects. We speculate that normal hadronic matter comes about through enforced phase transitions when such objects merge or collide, which also gives rise to the cosmic gamma-ray bursts.

  • 14.
    Fredriksson, Sverker
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hansson, Johan
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    A potential diquark in the proton1997In: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 75, no 1, p. 107-111Article in journal (Refereed)
    Abstract [en]

    A non-relativistic, QCD-based, potential quark model for the proton and the neutron inevitably predicts a spin-0 diquark structure with an rms radius of the order of 0.35rfm or smaller. We prove this by solving the (S wave) hamiltonian by De Rújula et al. with variational methods. It is essential to include all quark interactions and to use realistic test wave-functions. The protondelta mass difference, the magnetic moments and the nucleon charge radii can be reproduced only with wave functions that contain a mixture of quark-diquark and three-quark states. Approaches with just a quark-diquark component give incorrect magnetic moments, while those without diquarks lead to a too low proton-delta mass difference.

  • 15.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A hierarchy of cosmic compact objects: without black holes2007In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 38, no 1, p. 91-100Article in journal (Refereed)
    Abstract [en]

    We make the case for the existence of a, hitherto unknown and unobserved, hierarchy of ever more compact cosmic objects in the universe. This hypothesis is based on i) the assumption of "elementary" particle sub-constituents on several levels below the presently known, inspired by Glashow's "blooming desert", ii) the existence of nearly scale-invariant density fluctuations in the early universe, e.g. as predicted by inflationary models, iii) our own previous theoretical work showing that a class of objects considerably more compact than previously thought possible in astrophysics can exist. We also give several independent arguments strongly pointing towards the non-existence of black holes. Some brief suggestions on observational signals due to the hierarchy, both in collected astronomical data and in possible future observations, concludes the paper.

  • 16.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A possible experimental test to decide if quantum mechanical randomness is due to deterministic chaos in the underlying dynamics2000Report (Other academic)
    Abstract [en]

    A simple experiment using radioactive decay is proposed to test the possibility of a determinsistic, but chaotic, origin of quantum mechanical randomness.

  • 17.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A simple explanation of the nonappearance of physical gluons and quarks2002In: Canadian journal of physics (Print), ISSN 0008-4204, E-ISSN 1208-6045, Vol. 80, no 9, p. 1093-1097Article in journal (Refereed)
    Abstract [en]

    We show that the nonappearance of gluons and quarks as physical particles is a rigorous and automatic result of the full, i.e., nonperturbative, nonabelian nature of the color interaction in quantum chromodynamics (QCD). This makes it, in general, impossible to describe the color field as a collection of elementary quanta (gluons). Neither can a quark be an elementary quantum of the quark field, as the color field of which it is the source is itself a source, making isolated noninteracting quarks, crucial for a physical particle interpretation, impossible. In geometrical language, the impossibility of quarks and gluons as physical elementary particles arises due to the fact that the color Yang-Mills space does not have a constant trivial curvature. In QCD, the particles "gluons" and "quarks" are merely artifacts of an approximation method (the perturbative expansion) and are simply absent in the exact theory. This also coincides with the empirical, experimental evidence

  • 18.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    A simple solution to color confinement2000Report (Other academic)
    Abstract [en]

    We show that color confinement is a direct result of the nonabelian, i.e. nonlinear, nature of the color interaction in quantum chromodynamics. This makes it in general impossible to describe the color field as a collection of elementary quanta (gluons). A quark cannot be an elementary quanta of the quark field, as the color field of which it is the source is itself a source hence making isolated (noninteracting) quarks impossible. In geometrical language, the impossibility of quarks and gluons as physical particles arises due to the fact that the color Yang-Mills space does not have a constant trivial curvature.

  • 19.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Aspects of nonrelativistic quantum gravity2009In: Brazilian journal of physics, ISSN 0103-9733, E-ISSN 1678-4448, Vol. 39, no 4, p. 707-710Article in journal (Refereed)
    Abstract [en]

    A nonrelativistic approach to quantum gravity is studied. At least for weak gravitational fields it should be a valid approximation. Such an approach can be used to point out problems and prospects inherent in a more exact theory of quantum gravity, yet to be discovered. Nonrelativistic quantum gravity, e.g., shows promise for prohibiting black holes altogether (which would eliminate singularities and also solve the black hole information paradox), gives gravitational radiation even in the spherically symmetric case, and supports non-locality (quantum entanglement). Its predictions should also be testable at length scales well above the "Planck scale", by high-precision experiments feasible with existing technology.

  • 20.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Bell's Theorem and its tests: Proof that Nature is super-deterministic - not random2019Report (Other academic)
    Abstract [en]

    By analyzing the same Bell experiment in different reference frames we show that nature at its fundamental level is super-deterministic, not random, in contrast to what is indicated by orthodox quantum mechanics. Events - including the results of quantum mechanical measurements - in global space-time are fixed prior to measurement.

  • 21.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Big Bang på 15 minuter - Stora skrällen2008In: Allt om Vetenskap, ISSN 1652-3318, no 4, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 22.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Black Holes: Anybody out there?2016In: Electronic Journal of Theoretical Physics, ISSN 1729-5254, E-ISSN 1729-5254, Vol. 13, no 35, p. 91-94Article in journal (Refereed)
    Abstract [en]

    Using analytical results from both general relativity and quantum mechanics weshow that physical black holes probably do not exist. This would actually be a boon totheoretical physics, for example as:i) General relativity would then be globally valid in the (classical) physical universe, due to itsnon-singular nature.ii) The black hole information paradox would vanish.iii) No event horizon would mean no Hawking radiation, resolving the causal paradox that foran outside observer it takes an infinite time for the black hole to form whereas it evaporates infinite time.Astrophysical applications that seem to require black holes (quasars/AGNs, some binarysystems, stellar motions near the center of our galaxy, etc) can still be fulfilled by compactbut non-singular masses, M..

  • 23.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Black Holes: Anybody out there?2015Report (Refereed)
    Abstract [en]

    Using analytical results from both general relativity and quantummechanics we show that physical black holes probably do not exist.This would actually be a boon to theoretical physics, for example as:i) General relativity would then be globally valid in the (classical)physical universe, due to its non-singular nature.ii) The black hole information paradox would vanish.iii) No event horizon would mean no Hawking radiation, resolving thecausal paradox that for an outside observer it takes an innite timefor the black hole to form whereas it evaporates in nite time.Astrophysical applications that seem to require black holes (quasars/AGNs,stellar motions near the center of our galaxy, etc) can still be fullledby compact but non-singular masses, M.

  • 24.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Kaosteorin på 15 minuter - Världen är inget urverk2007In: Allt om Vetenskap, ISSN 1652-3318, no 11, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 25.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Kosmologin på 15 minuter - Läran om allt2008In: Allt om Vetenskap, ISSN 1652-3318, no 1, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 26.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Kvantfysiken på 15 minuter: världen är (o)sannolik2007In: Allt om Vetenskap, ISSN 1652-3318, no 9, p. 106-109Article in journal (Other (popular science, discussion, etc.))
  • 27.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Kvantgravitationen på 15 minuter - Den gäckande teorin2008In: Allt om Vetenskap, ISSN 1652-3318, no 3, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 28.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Livet, Universum & Allting: Samlade Populärvetenskapliga Krönikor2019Book (Other (popular science, discussion, etc.))
  • 29.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Microscopic gravity?2014Report (Refereed)
  • 30.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Moderna Fysiken på 15 Minuter2017Book (Other (popular science, discussion, etc.))
  • 31.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Newtonian Quantum Gravity2006Report (Other academic)
  • 32.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Newtonian quantum gravity2010In: Physics essays, ISSN 0836-1398, Vol. 23, no 1, p. 53-56Article in journal (Refereed)
    Abstract [en]

    A Newtonian approach to quantum gravity is studied. At least for weak gravitational fields, it should be a valid approximation. Such an approach can be used to point out problems and prospects inherent in a more exact theory of quantum gravity, yet to be discovered. Newtonian quantum gravity, e.g., shows promise for prohibiting black holes altogether (which would eliminate singularities and also solve the black hole information paradox), gives gravitational radiation even in the spherically symmetric case, and supports nonlocality (quantum entanglement). Its predictions should also be testable at length scales well above the "Planck scale" by high-precision experiments feasible with existing technology.

  • 33.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    No-Go of Quantized General Relativity2015Report (Refereed)
  • 34.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    No-Go of Quantized General Relativity2016In: Advanced Studies in Theoretical Physics, ISSN 1313-1311, E-ISSN 1314-7609, Vol. 10, no 8, p. 415-420Article in journal (Refereed)
    Abstract [en]

    In this article we show: i) The impossibility of actively “quantizing” general relativity. ii) That the key to quantum gravity - a theory for “deducing” the macroscopic theory of general relativity - is to explain, from a fundamental microscopic theory, why the inertial mass is proportional to the gravitational mass, mi=mg = const, in the classical limit

  • 35.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nonlinear gauge interactions: a possible solution to the "measurement problem" in quantum mechanics2010In: Physics essays, ISSN 0836-1398, Vol. 23, no 2, p. 237-241Article in journal (Refereed)
    Abstract [en]

    Two fundamental and unsolved problems in physics are as follows: (i) the resolution of the "measurement problem" in quantum mechanics and (ii) the quantization of strongly nonlinear (non-Abelian) gauge theories. The aim of this paper is to suggest that these two problems might be linked and that a mutual simultaneous solution to both might exist. We propose that the mechanism responsible for the "collapse of the wave function" in quantum mechanics is the nonlinearities already present in the theory via non-Abelian gauge interactions. Unlike all other models of spontaneous collapse, our proposal is, to the best of our knowledge, the only one that does not introduce any new elements into the theory. A possible experimental test of the model would be to compare the coherence lengths-here defined as the distance over which the quantum mechanical superposition is still valid-e.g., electrons and photons in a double-slit experiment. The electrons should have a finite coherence length, while photons should have a much longer coherence length (in principle infinite, if gravity-a very weak effect indeed unless we approach the Planck scale-is ignored).

  • 36.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nonlinear gauge interactions: a solution to the 'measurement problem' in quantum mechanics?2000Report (Other academic)
    Abstract [en]

    We propose that the mechanism responsible for the ``collapse of the wave function" (or "decoherence" in its broadest meaning) in quantum mechanics is the nonlinearities already present in the theory via nonabelian gauge interactions. Unlike all other models of spontaneous collapse, our proposal is, to the best of our knowledge, the only one which does not introduce any new elements into the theory. Indeed, unless the gauge interaction nonlinearities are not used for exactly this purpose, one must then explain why the violation of the superposition principle which they introduce does not destroy quantum mechanics. A possible experimental test of the model would be to compare the coherence lengths for, e.g., electrons and photons in a double-slit experiment. The electrons should have a finite coherence length, while photons should have a much longer (in principle infinite) coherence length.

  • 37.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    On the Origin of Elementary Particle Masses2012Report (Refereed)
  • 38.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Partikelfysiken på 15 minuter - Vad är fundamentalt?2007In: Allt om Vetenskap, ISSN 1652-3318, Vol. 12, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 39.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Physical Origin of Elementary Particle Masses2014In: Electronic Journal of Theoretical Physics, ISSN 1729-5254, E-ISSN 1729-5254, Vol. 11, no 30, p. 87-100Article in journal (Refereed)
  • 40.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Physical Origin of Elementary Particle Masses2013Report (Refereed)
  • 41.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Quantivity?2017Report (Other academic)
  • 42.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    “Quantum machine” to solve quantum “measurement problem”?2014Report (Refereed)
  • 43.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    "Quantum machine" to solve quantum "measurement problem"?2015In: Advanced Studies in Theoretical Physics, ISSN 1313-1311, E-ISSN 1314-7609, Vol. 9, no 5, p. 233-236Article in journal (Refereed)
    Abstract [en]

    Recently a study of the rst superposed mechanical quantum object(\machine") visible to the naked eye was published [1]. However, as weshow, it turns out that if the object would actually be observed, i.e.would interact with an optical photon, the quantum behavior shouldvanish. This, the actual observation, has long been suspected in manyinterpretations of quantum mechanics to be what makes the transitionquantum ! classical, but so far it has not been available for direct ex-perimental study in a mechanical system. We show how any interaction,even a purely quantum one, of sucient strength can constitute a physi-cal \measurement" - essentially the emergence of an eectively classicalobject - active observation thus being a sucient but not necessary cri-terion. So it seems we have in this case of the \quantum machine" aunique possibility to study, and possibly solve, the long-standing \mea-surement problem" of quantum mechanics.

  • 44.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Reality or locality?: Proposed test to decide how nature breaks Bell's inequality2012In: Physics Research International, ISSN 2090-2220, E-ISSN 2090-2239, Vol. 2012, article id 352543Article in journal (Refereed)
  • 45.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Relativitetsteorin på 15 minuter: allt är inte alls relativt2007In: Allt om Vetenskap, ISSN 1652-3318, no 10, p. 106-109Article in journal (Other (popular science, discussion, etc.))
  • 46.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Reply to comment on 'A Simple explanation of the nonappearance of physical gluons and quarks'2003In: Canadian journal of physics (Print), ISSN 0008-4204, E-ISSN 1208-6045, Vol. 81, p. 893-894Article in journal (Other academic)
    Abstract [en]

    This is the reply to a comment by Andreas Aste on a previous article of mine in Can.J.Phys. The counter-arguments used by Aste utilize a mathematical limit without physical meaning. We still contend that in QCD, the particles ``gluons'' and ``quarks'' are merely artifacts of an approximation method (the perturbative expansion) and are simply absent in the exact theory.

  • 47.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Strängteorin på 15 minuter - Teorin om allt... eller inget?2008In: Allt om Vetenskap, ISSN 1652-3318, no 2, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 48.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Svarta hål på 15 minuter - Fysikens slut?2008In: Allt om Vetenskap, ISSN 1652-3318, no 5, p. 104-108Article in journal (Other (popular science, discussion, etc.))
  • 49.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    The 10 Biggest Unsolved Problems in Physics2015In: International Journal of Modern Physics and Applications, ISSN 2381-6945, Vol. 1, no 1, p. 12-16Article in journal (Refereed)
    Abstract [en]

    In 1900, the British physicist Lord Kelvin declared: “There is nothing new to discover in physics. All that remains is to more accurately measure its quantities.” In the same year quantum physics was born and three decades later it, and Einstein’s theory of relativity, had completely revolutionized and transformed physics. Today, hardly anyone would dare say that our knowledge of the universe, and everything in it, is almost complete. On the contrary, every new discovery appears to open a Pandora’s Box of larger and deeper issues. I have selected some of today’s biggest unsolved riddles in physics. Just like Moses, I stop arbitrarily at 10. Here follow these “Ten Com...plications” with a brief explanation/justification. They may be seen as a roadmap for future important work.

  • 50.
    Hansson, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    The 10 Biggest Unsolved Problems in Physics2015Report (Refereed)
12 1 - 50 of 74
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf