| 1. |
- Sjöqvist, Erik, et al.
(författare)
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Conceptual aspects of geometric quantum computation
- 2016
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Ingår i: Quantum Information Processing. - : Springer Science and Business Media LLC. - 1570-0755 .- 1573-1332. ; 15:10, s. 3995-4011
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Tidskriftsartikel (refereegranskat)abstract
- Geometric quantum computation is the idea that geometric phases can be used to implement quantum gates, i.e., the basic elements of the Boolean network that forms a quantum computer. Although originally thought to be limited to adiabatic evolution, controlled by slowly changing parameters, this form of quantum computation can as well be realized at high speed by using nonadiabatic schemes. Recent advances in quantum gate technology have allowed for experimental demonstrations of different types of geometric gates in adiabatic and nonadiabatic evolution. Here, we address some conceptual issues that arise in the realizations of geometric gates. We examine the appearance of dynamical phases in quantum evolution and point out that not all dynamical phases need to be compensated for in geometric quantum computation. We delineate the relation between Abelian and non-Abelian geometric gates, and find an explicit physical example where the two types of gates coincide. We identify differencies and similarities between adiabatic and nonadiabatic realizations of quantum computation based on non-Abelian geometric phases.
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| 2. |
- Talyzin, Alexandr, 1969-, et al.
(författare)
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Brodie vs Hummers graphite oxides for preparation of multi-layered materials
- 2017
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Ingår i: Carbon. - : Elsevier. - 0008-6223 .- 1873-3891. ; 115, s. 430-440
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Tidskriftsartikel (refereegranskat)abstract
- Graphite oxides synthesized by one and two step Brodie oxidation (BGO) and Hummers (HGO) methods were analyzed by a variety of characterization methods in order to evaluate the reasons behind the difference in their properties. It is found that the Brodie method results in a higher relative amount of hydroxyl groups and a more homogeneous overall distribution of functional groups over the planar surface of the graphene oxide flakes. The higher number of carbonyl and carboxyl groups in HGO, detected by several methods, including XPS, NMR and FTIR, unavoidably results in defects of the graphene "skeleton", holes and overall disruption of the carbon-carbon bond network, stronger deviation from planar flake shape and poor ordering of the graphene oxide layers. It is also suggested that functional groups in HGO are less homogeneously distributed over the flake surface, forming some nanometer-sized graphene areas. The presence of differently oxidized areas on the GO surface results in inhomogeneous solvation and hydration of HGO and effects of inter- and intra-stratification. The proposed interpretation of the data explains the higher mechanical strength of multi-layered BGO membranes/papers, which are also less affected by humidity changes, thus providing an example of a membrane property superior to that of HGO. (C) 2016 Published by Elsevier Ltd.
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| 3. |
- Andersson, Ole, et al.
(författare)
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Device-independent certification of two bits of randomness from one entangled bit and Gisin's elegant Bell inequality
- 2018
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 97:1
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Tidskriftsartikel (refereegranskat)abstract
- We prove that as conjectured by Acín et al. [Phys. Rev. A 93, 040102(R) (2016)], two bits of randomness can be certified in a device-independent way from one bit of entanglement using the maximal quantum violation of Gisin's elegant Bell inequality. This suggests a surprising connection between maximal entanglement, complete sets of mutually unbiased bases, and elements of symmetric informationally complete positive operator-valued measures, on one side, and the optimal way of certifying maximal randomness, on the other.
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| 4. |
- Fredlund, Tobias, et al.
(författare)
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Towards addressing transient learning challenges in undergraduate physics: An example from electrostatics
- 2015
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Ingår i: European journal of physics. - : IOP Publishing. - 0143-0807 .- 1361-6404. ; 36:5
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Tidskriftsartikel (refereegranskat)abstract
- In this article we characterize transient learning challenges as learning challenges that arise out of teaching situations rather than conflicts with prior knowledge. We propose that these learning challenges can be identified by paying careful attention to the representations that students produce. Once a transient learning challenge has been identified, teachers can create interventions to address it. By illustration, we argue that an appropriate way to design such interventions is to create variation around the disciplinary-relevant aspects associated with the transient learning challenge.References:Bowden J and Marton F 1998 The University of Learning: Beyond Quality and Competence in Higher Education (London: Kogan Page)Chen Z and Gladding G 2014 How to make a good animation: a grounded cognition model of how visual representation design affects the construction of abstract physics knowledge Phys. Rev. ST— Phys. Educ. Res. 10 010111Coppens P, De Cock M and Kautz C 2012 Student understanding of filters in analog electronics lab courses Proc. 40th Ann. Proc. SEFI Conf. (Thessaloniki, Greece)Cummings K 2011 A developmental history of physics education research The Second Committee Meeting on the Status, Contributions, and Future Directions of Discipline-Based Education Research (http://sites.nationalacademies.org/xpedio/groups/dbassesite/documents/webpage/ dbasse_072580.pdf)Domert D, Linder C and Ingerman Å 2005 Probability as a conceptual hurdle to understanding one- dimensional quantum scattering and tunnelling Eur. J. Phys. 26 47–59Driver R and Erickson G 1983 Theories-in-action: some theoretical and empirical issues in the study of students’ conceptual frameworks in science Stud. Sci. Educ. 10 37–60Fraser J M, Timan A L, Miller K, Dowd J E, Tucker L and Mazur E 2014 Teaching and physics education research: bridging the gap Rep. Prog. Phys. 77 1–17Fredlund, T, Airey, J and Linder, C (2012) Exploring the role of physics representations: an illustrative example from students sharing knowledge about refraction. Eur. J. Phys. 33, 657–66Fredlund, T, Airey, J and Linder, C (2015) Enhancing the possibilities for learning: variation of disciplinary-relevant aspects in physics representations. Eur. J. Phys. 36, 055001Hammer D 2000 Student resources for learning introductory physics Phys. Educ. Res., Am. J. Phys. Suppl. 68 52–9Helm H and Novak J D (ed) 1983 Proc. Int. Seminar on Misconceptions in Science and Mathematics (Ithaca, NY: Department of Education, Cornell University)Heron P R L and Hazelton R 2013 Interpreting students’ errors: examples from electrostatics Proc. ESERA 2013 (Nicosia, Cyprus) pp 82–9Ingerman Å, Berge M and Booth S 2009a Physics group work in a phenomenographic perspective— learning dynamics as the experience of variation and relevance Eur. J. Eng. Educ. 34 349–58Ingerman Å, Linder C and Marshall D 2009b The learners’ experience of variation: following students’ threads of learning physics in computer simulation sessions Instr. Sci. 37 273–92Khan Academy 2014 Electric potential at a point in space (www.khanacademy.org/test-prep/mcat/ physical-processes/electrostatics-1/v/electric-potential-at-a-point-in-space)Knight R D 2002 Five Easy Lessons: Strategies for Successful Physics Teaching (San Fransisco: Addison-Wesley)Marton F 2015 Necessary Conditions of Learning (New York: Routledge)Marton F and Booth S 1997 Learning and Awareness (Mahwah: Lawrence Erlbaum Associates)Marton F and Pang M F 2006 On some necessary conditions of learning J. Learn. Sci. 15 193–220Marton F and Tsui A B M 2004 Classroom Discourse and the Space of Learning (Mahwah: Lawrence Erlbaum Associates)McDermott L C 1991 Millikan lecture 1990: what we teach and what is learned–closing the gap Am. J. Phys. 59 301–15McDermott L C and Redish E F 1999 Resource letter PER-1: physics education research Am. J. Phys. 67 755–67McDermott L C and Shaffer P S 2002 Tutorials in Introductory Physics 1st edn (Upper Saddle River, NJ: Prentice-Hall)Nordling C and Österman J 2006 Physics Handbook: for Science and Engineering (Lund: Studentlitteratur)Planinic M 2006 Assessment of difficulties of some conceptual areas from electricity and magnetism using the conceptual survey of electricity and magnetism Am. J. Phys. 74 1143–8Prather E E, Rudolph A L, Brissenden G and Schlingman W M 2009 A national study assessing the teaching and learning of introductory astronomy: I. The effect of interactive instruction Am. J. Phys. 77 320–30Reif F 2008 Applying Cognitive Science to Education: Thinking and Learning in Scientific and Other Complex Domains (Cambridge: MIT Press)Reif F and Larkin J H 1991 Cognition in scientific and everyday domains: comparison and learning implications J. Res. Sci. Teach. 28 733–60Roth W-M and McGinn M K 1998 Inscriptions: toward a theory of representing as social practice Rev. Educ. Res. 68 35–59Sayre E C and Heckler A F 2009 Peaks and decays of student knowledge in an introductory E&M course Phys. Rev. ST—Phys. Educ. Res. 5 013101Tao P-K and Gunstone R F 1999 The process of conceptual change in force and motion during computer-supported physics instruction J. Res. Sci. Teach. 36 859–82Tuminaro J and Redish E F 2007 Elements of a cognitive model of physics problem solving: epistemic games Phys. Rev. ST—Phys. Educ. Res. 3 020201Viennot L 2001 Reasoning in Physics: the Part of Common Sense (Dordrecht: Kluwer Publishers) Young H D and Freedman R A 2004 University Physics with Modern Physics (San Francisco: Pearson)
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| 5. |
- Milstead, David A., et al.
(författare)
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Modelling radiation damage to pixel sensors in the ATLAS detector
- 2019
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS experiment at the LHC. Given their close proximity to the interaction point, these detectors will be exposed to an unprecedented amount of radiation over their lifetime. The current pixel detector will receive damage from non-ionizing radiation in excess of 1015 1 MeV neq/cm2, while the pixel detector designed for the high-luminosity LHC must cope with an order of magnitude larger fluence. This paper presents a digitization model incorporating effects of radiation damage to the pixel sensors. The model is described in detail and predictions for the charge collection efficiency and Lorentz angle are compared with collision data collected between 2015 and 2017 (≤ 10 1 MeV neq/cm2). © 2019 CERN for the benefit of the ATLAS collaboration. Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.
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| 6. |
- Aartsen, M. G., et al.
(författare)
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Search for dark matter annihilation in the Galactic Center with IceCube-79
- 2015
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 75:10
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Tidskriftsartikel (refereegranskat)abstract
- The Milky Way is expected to be embedded in a halo of dark matter particles, with the highest density in the central region, and decreasing density with the halo-centric radius. Dark matter might be indirectly detectable at Earth through a flux of stable particles generated in dark matter annihilations and peaked in the direction of the Galactic Center. We present a search for an excess flux of muon (anti-) neutrinos from dark matter annihilation in the Galactic Center using the cubic-kilometer-sized IceCube neutrino detector at the South Pole. There, the Galactic Center is always seen above the horizon. Thus, new and dedicated veto techniques against atmospheric muons are required to make the southern hemisphere accessible for IceCube. We used 319.7 live-days of data from IceCube operating in its 79-string configuration during 2010 and 2011. No neutrino excess was found and the final result is compatible with the background. We present upper limits on the self-annihilation cross-section, < sAv >, for WIMP masses ranging from 30GeV up to 10TeV, assuming cuspy (NFW) and flat-cored (Burkert) dark matter halo profiles, reaching down to similar or equal to 4 . 10(-24) cm(3) s(-1), and similar or equal to 2.6 . 10(-23) cm(3) s(-1) for the nu(nu) over bar channel, respectively.
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| 7. |
- Lindwall, Katrin, 1959-, et al.
(författare)
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Maker Tour - Mot nya höjder : Make IT flow, del 2
- 2018
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Annan publikation (populärvet., debatt m.m.)abstract
- Utmaningarna är en del av projektet Maker tour - Mot nya höjder ( tidigare Mot nya höjder). Projektets mål är att öka intresset för naturvetenskap, teknik och matematik bland skolelever.Läs gärna mer på http://motnyahojder.com/
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| 8. |
- Lindwall, Katrin, 1959-, et al.
(författare)
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Maker tour: mot nya höjder : make space HT-19
- 2019
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Annan publikation (populärvet., debatt m.m.)abstract
- Utmaningarna är en del av projektet Maker tour - Mot nya höjder (tidigare Mot nya höjder). Projektets mål är att öka intresset för naturvetenskap, teknik och matematik bland skolelever.
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| 9. |
- Lindwall, Katrin, 1959-, et al.
(författare)
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Maker tour: mot nya höjder : make IT shine HT-18
- 2018
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Annan publikation (populärvet., debatt m.m.)abstract
- Utmaningarna är en del av projektet Maker tour - Mot nya höjder (tidigare Mot nya höjder). Projektets mål är att öka intresset för naturvetenskap, teknik och matematik bland skolelever.
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| 10. |
- Lindwall, Katrin, 1959-, et al.
(författare)
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Mot nya höjder : Make IT happen våren 2016
- 2016
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Annan publikation (populärvet., debatt m.m.)abstract
- Utmaningarna är en del av projektet Mot nya höjder ( från 2018 Maker tour - Mot nya höjder). Projektets mål är att öka intresset för naturvetenskap, teknik och matematik bland skolelever.Läs gärna mer på www.motnyahojder.com
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