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Author |
Casas, F.; Oteo, J.A.; Ros, J. |
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Title |
Unitary transformations depending on a small parameter |
Type |
Journal Article |
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Year |
2012 |
Publication  |
Proceedings of the Royal Society A |
Abbreviated Journal |
Proc. R. Soc. A |
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Volume |
468 |
Issue |
2139 |
Pages |
685-700 |
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Keywords |
perturbation theory; quantum mechanics; unitary transformation; Magnus expansion |
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Abstract |
We formulate a unitary perturbation theory for quantum mechanics inspired by the Lie-Deprit formulation of canonical transformations. The original Hamiltonian is converted into a solvable one by a transformation obtained through a Magnus expansion. This ensures unitarity at every order in a small parameter. A comparison with the standard perturbation theory is provided. We work out the scheme up to order ten with some simple examples. |
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Address |
[Oteo, J. A.; Ros, J.] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: rosj@uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Royal Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1364-5021 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300185400005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
893 |
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Author |
Alioli, S.; Fuster, J.; Irles Quiles, A.; Moch, S.; Uwer, P.; Vos, M. |
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Title |
A new observable to measure the top quark mass at hadron colliders |
Type |
Journal Article |
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Year |
2012 |
Publication |
Pramana-Journal of Physics |
Abbreviated Journal |
Pramana-J. Phys. |
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Volume |
79 |
Issue |
4 |
Pages |
809-812 |
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Keywords |
Top quark; mass; pole mass; NLO; cross-section; t(t)over-bar plus jet; POWHEG; perturbative QCD |
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Abstract |
The t (t) over bar + jet + X differential cross-section in proton-proton collisions at 7 TeV centre of mass energy is investigated with respect to its sensitivity to the top quark mass. The analysis includes higher order QCD corrections at NLO. The impact of the renormalization scale (mu(R)), the factorization (mu(F)) scale and of the choice of different proton's PDF (parton distribution function) has been evaluated. In this study it is concluded that differential jet rates offer a promising option for alternative mass measurements of the top quark, with theoretical uncertainties below 1 GeV. |
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Address |
[Fuster, Juan; Irles, Adrian; Vos, Marcel] Univ Valencia, Ctr Mixte, CSIC, IFIC, E-46071 Valencia, Spain, Email: airqui@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Indian Acad Sciences |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-4289 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000310875900021 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1200 |
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Author |
Botella-Soler, V.; Valderrama, M.; Crepon, B.; Navarro, V.; Le Van Quyen, M. |
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Title |
Large-Scale Cortical Dynamics of Sleep Slow Waves |
Type |
Journal Article |
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Year |
2012 |
Publication |
Plos One |
Abbreviated Journal |
PLoS One |
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Volume |
7 |
Issue |
2 |
Pages |
e30757 - 10pp |
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Keywords |
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Abstract |
Slow waves constitute the main signature of sleep in the electroencephalogram (EEG). They reflect alternating periods of neuronal hyperpolarization and depolarization in cortical networks. While recent findings have demonstrated their functional role in shaping and strengthening neuronal networks, a large-scale characterization of these two processes remains elusive in the human brain. In this study, by using simultaneous scalp EEG and intracranial recordings in 10 epileptic subjects, we examined the dynamics of hyperpolarization and depolarization waves over a large extent of the human cortex. We report that both hyperpolarization and depolarization processes can occur with two different characteristic time durations which are consistent across all subjects. For both hyperpolarization and depolarization waves, their average speed over the cortex was estimated to be approximately 1 m/s. Finally, we characterized their propagation pathways by studying the preferential trajectories between most involved intracranial contacts. For both waves, although single events could begin in almost all investigated sites across the entire cortex, we found that the majority of the preferential starting locations were located in frontal regions of the brain while they had a tendency to end in posterior and temporal regions. |
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Address |
[Botella-Soler, Vicente] Univ Valencia, Dept Fis Teor, CSIC, Valencia, Spain, Email: quyen@t-online.de |
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Corporate Author |
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Thesis |
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Publisher |
Public Library Science |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-6203 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000302853600065 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
986 |
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Author |
Valderrama, M.; Crepon, B.; Botella-Soler, V.; Martinerie, J.; Hasboun, D.; Alvarado-Rojas, C.; Baulac, M.; Adam, C.; Navarro, V.; Le Van Quyen, M. |
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Title |
Human Gamma Oscillations during Slow Wave Sleep |
Type |
Journal Article |
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Year |
2012 |
Publication |
Plos One |
Abbreviated Journal |
PLoS One |
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Volume |
7 |
Issue |
4 |
Pages |
e33477 - 14pp |
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Keywords |
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Abstract |
Neocortical local field potentials have shown that gamma oscillations occur spontaneously during slow-wave sleep (SWS). At the macroscopic EEG level in the human brain, no evidences were reported so far. In this study, by using simultaneous scalp and intracranial EEG recordings in 20 epileptic subjects, we examined gamma oscillations in cerebral cortex during SWS. We report that gamma oscillations in low (30-50 Hz) and high (60-120 Hz) frequency bands recurrently emerged in all investigated regions and their amplitudes coincided with specific phases of the cortical slow wave. In most of the cases, multiple oscillatory bursts in different frequency bands from 30 to 120 Hz were correlated with positive peaks of scalp slow waves (“IN-phase'' pattern), confirming previous animal findings. In addition, we report another gamma pattern that appears preferentially during the negative phase of the slow wave (”ANTI-phase'' pattern). This new pattern presented dominant peaks in the high gamma range and was preferentially expressed in the temporal cortex. Finally, we found that the spatial coherence between cortical sites exhibiting gamma activities was local and fell off quickly when computed between distant sites. Overall, these results provide the first human evidences that gamma oscillations can be observed in macroscopic EEG recordings during sleep. They support the concept that these high-frequency activities might be associated with phasic increases of neural activity during slow oscillations. Such patterned activity in the sleeping brain could play a role in off-line processing of cortical networks. |
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Address |
[Valderrama, Mario; Crepon, Benoit; Martinerie, Jacques; Hasboun, Dominique; Alvarado-Rojas, Catalina; Baulac, Michel; Adam, Claude; Navarro, Vincent; Le Van Quyen, Michel] Univ Paris 06, Ctr Rech Inst Cerveau & Moelle Epiniere CRICM, INSERM,UMRS 975, Hop La Pitie Salpetriere,CNRS,UMR 7225, Paris, France, Email: quyen@t-online.de |
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Corporate Author |
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Thesis |
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Publisher |
Public Library Science |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-6203 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000304855200013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1058 |
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| Permanent link to this record |
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Author |
HADES Collaboration (Lapidus, K. et al); Diaz, J.; Gil, A. |
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Title |
The HADES-at-FAIR project |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physics of Atomic Nuclei |
Abbreviated Journal |
Phys. Atom. Nuclei |
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Volume |
75 |
Issue |
5 |
Pages |
589-593 |
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Keywords |
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Abstract |
After the completion of the experimental program at SIS18 the HADES setup will migrate to FAIR, where it will deliver high-quality data for heavy-ion collisions in an unexplored energy range of up to 8 A GeV. In this contribution, we briefly present the physics case, relevant detector characteristics and discuss the recently completed upgrade of HADES. |
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Address |
[Lapidus, K.; Chen, J. C.; Epple, E.; Fabbietti, L.; Lalik, R.; Muenzer, R.; Schmah, A.; Siebenson, J.] Excellence Cluster Origin & Struct Universe, Garching, Germany, Email: kirill.lapidus@ph.tum.de |
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Corporate Author |
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Thesis |
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Publisher |
Maik Nauka/Interperiodica/Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1063-7788 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000304621800011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1046 |
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| Permanent link to this record |
