17 research outputs found

    Quantum optimal control theory applied to transitions in diatomic molecules

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    Quantum optimal control theory is applied to control electric dipole transitions in a real multilevel system. The specific system studied in the present work is comprised of a multitude of hyperfine levels in the electronic ground state of the OH molecule. Spectroscopic constants are used to obtain accurate energy eigenstates and electric dipole matrix elements. The goal is to calculate the optimal time-dependent electric field that yields a maximum of the transition probability for a specified initial and final state. A further important objective was to study the detailed quantum processes that take place during such a prescribed transition in a multilevel system. Two specific transitions are studied in detail. The computed optimal electric fields as well as the paths taken through the multitude of levels reveal quite interesting quantum phenomena

    Hyperfine, rotational and Zeeman structure of the lowest vibrational levels of the 87^{87}Rb2_2 \tripletex state

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    We present the results of an experimental and theoretical study of the electronically excited \tripletex state of 87^{87}Rb2_2 molecules. The vibrational energies are measured for deeply bound states from the bottom up to v=15v'=15 using laser spectroscopy of ultracold Rb2_2 Feshbach molecules. The spectrum of each vibrational state is dominated by a 47\,GHz splitting into a \cog and \clg component caused mainly by a strong second order spin-orbit interaction. Our spectroscopy fully resolves the rotational, hyperfine, and Zeeman structure of the spectrum. We are able to describe to first order this structure using a simplified effective Hamiltonian.Comment: 10 pages, 7 figures, 2 table

    Photoassociation of ultracold atoms

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    Oppgaven ser på muligheten for å buke fotoassosiasjon som metode for å produsere kalde molekyler. Det gjøres eksplisitte regninger for Litium molekylet, og undersøkes i hvilken grad vi kan forvente å produsere ultrakalde Litium molekyler baser på fotoassosisjon. Oppgaven tar også opp tema som BEC-BCS overgang, Feshbach resonanser, potensialkurver, vibrasjonsnivå, spredningsteori ved ultrakalde temperaturer og tunneling for en vilkårlig potensialbarriære

    Cold collisions of atoms and molecules

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    Molecular hyperfine parameters in the 1 

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    Magnetic hyperfine parameters have been computed for the 1   3Σu+ and 1   3Σg+ states of Li2,Na2,K2 and Rb2. The parameters were computed with MCSCF wavefunctions and the calculations were repeated for a series of internuclear distances. The results are compared with a recent observation of the hyperfine structure in Rb2, and to the atomic hyperfine parameters. The available empirical data are reproduced with high accuracy. For the present systems, the molecular hyperfine parameters are largely determined by the corresponding atomic hyperfine interactions. The computed molecular parameters at the dissociation limit deviate at most 11% from the experimentally determined atomic ones

    Quantum optimal control theory applied to transitions in diatomic molecules

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    Quantum optimal control theory is applied to control electric dipole transitions in a real multilevel system. The specific system studied in the present work is comprised of a multitude of hyperfine levels in the electronic ground state of the OH molecule. Spectroscopic constants are used to obtain accurate energy eigenstates and electric dipole matrix elements. The goal is to calculate the optimal time-dependent electric field that yields a maximum of the transition probability for a specified initial and final state. A further important objective was to study the detailed quantum processes that take place during such a prescribed transition in a multilevel system. Two specific transitions are studied in detail. The computed optimal electric fields as well as the paths taken through the multitude of levels reveal quite interesting quantum phenomena

    Hvorfor antall arbeidskrav bør reduseres

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    Sammendrag I litteraturen om vurdering fremheves gjerne formativ vurdering, på empirisk grunnlag, som spesielt læringsproduktiv. Likevel er formativ vurdering et sjeldent innslag i ingeniørutdanning i Norge. Ingeniørstudenter blir ofte vurdert, men nesten utelukkende med sertifisering og rangering som hovedsiktemål. I denne artikkelen beskrives det nåværende vurderingsregimet og spesielt den omfattende bruken av arbeidskrav. Problemet med den rådende praksis er at den formative vurderingen ikke får den posisjonen den fortjener og studenter, emneansvarlige og institusjoner går glipp av de ikke ubetydelige fordelene som formativ vurdering kan gi. Et konkret undervisningsopplegg med formativ vurdering i fokus beskrives og evalueres

    Molecular hyperfine parameters in the 1 3Su+ and 1 3Sg+ states of Li2, Na2, K2 and Rb2

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    Magnetic hyperfine parameters have been computed for the 1 3 Σ u + and 1 3 Σ g + states of Li2 ,Na2 ,K2 and Rb2. The parameters were computed with MCSCF wavefunctions and the calculations were repeated for a series of internuclear distances. The results are compared with a recent observation of the hyperfine structure in Rb2, and to the atomic hyperfine parameters. The available empirical data are reproduced with high accuracy. For the present systems, the molecular hyperfine parameters are largely determined by the corresponding atomic hyperfine interactions. The computed molecular parameters at the dissociation limit deviate at most 11% from the experimentally determined atomic ones

    Medstudentvurdering i matematikk og fysikk

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    Høsten 2014 ble det gjort endringer i begynnerundervisningen i matematikk og fysikk ved ett av studieprogrammene ved Høgskolen i Oslo og Akershus. Alle arbeidskravene ble fjernet, og medstudentvurdering ble innført. Målet er å gi studentene rask tilbakemelding på arbeidet deres, og stimulere til jevn og kontinuerlig arbeidsinnsats underveis. Erfaringene så langt er at studentene arbeider et riktig antall timer per uke, mens studentenes selvrapporterte utbytte av medstudentvurderingen er varierende. I denne artikkelen presenteres bakgrunnen for de innførte endringene, sammen med en konkret beskrivelse av de ulike formene for medstudentvurdering som forfatterne har forsøkt. Til slutt oppsummeres og diskuteres erfaringene så langt.https://www.idunn.no/uniped/2015/04/medstudentvurdering_imatematikk_og_fysik

    Mandatory coursework assignments can be, and should be, eliminated!

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    Formative assessment can serve as a catalyst for increased student effort and student learning. Yet, many engineering degree programs are dominated by summative assessment and make limited use of formative assessment. The present case study serves as an example on how formative assessment can be used strategically to increase student effort and improve student learning. Within five courses of an engineering bachelor degree program in Norway, the mandatory coursework assignments were removed and replaced by formative-only assessment. To facilitate the formative assessment, weekly student peer-assessment sessions were introduced. The main findings include an increase in student study hours and improved student performance on the examinations. Finally, interviews were conducted by an external consultant in an effort to identify key factors that attributed to the positive outcome
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