@article{14753, abstract = {Several fixed-target experiments reported J/ψ and ϒ polarizations, as functions of Feynman x (xF) and transverse momentum (PT), in three different frames, using different combinations of beam particles, target nuclei, and collision energies. Despite the diverse and heterogeneous picture formed by these measurements, a detailed look allows us to discern qualitative physical patterns that inspire a simple empirical model. This data-driven scenario offers a good quantitative description of the J/ψ and ϒ(1S) polarizations measured in proton- and pion-nucleus collisions, in the xF 0.5 domain: more than 80 data points (not statistically independent) are well reproduced with only one free parameter. This study sets the context for future low-PT quarkonium polarization measurements in proton- and pion-nucleus collisions, such as those to be made by the AMBER experiment, and shows that such measurements provide significant constraints on the poorly-known parton distribution functions of the pion.}, author = {Faccioli, Pietro and Krätschmer, Ilse and Lourenço, Carlos}, issn = {1873-2445}, journal = {Physics Letters B}, keywords = {Nuclear and High Energy Physics}, publisher = {Elsevier}, title = {{Low-pT quarkonium polarization measurements: Challenges and opportunities}}, doi = {10.1016/j.physletb.2023.137871}, volume = {840}, year = {2023}, } @article{13277, abstract = {Recent experimental advances have inspired the development of theoretical tools to describe the non-equilibrium dynamics of quantum systems. Among them an exact representation of quantum spin systems in terms of classical stochastic processes has been proposed. Here we provide first steps towards the extension of this stochastic approach to bosonic systems by considering the one-dimensional quantum quartic oscillator. We show how to exactly parameterize the time evolution of this prototypical model via the dynamics of a set of classical variables. We interpret these variables as stochastic processes, which allows us to propose a novel way to numerically simulate the time evolution of the system. We benchmark our findings by considering analytically solvable limits and providing alternative derivations of known results.}, author = {Tucci, Gennaro and De Nicola, Stefano and Wald, Sascha and Gambassi, Andrea}, issn = {2666-9366}, journal = {SciPost Physics Core}, keywords = {Statistical and Nonlinear Physics, Atomic and Molecular Physics, and Optics, Nuclear and High Energy Physics, Condensed Matter Physics}, number = {2}, publisher = {SciPost Foundation}, title = {{Stochastic representation of the quantum quartic oscillator}}, doi = {10.21468/scipostphyscore.6.2.029}, volume = {6}, year = {2023}, } @article{12232, abstract = {We derive a precise asymptotic formula for the density of the small singular values of the real Ginibre matrix ensemble shifted by a complex parameter z as the dimension tends to infinity. For z away from the real axis the formula coincides with that for the complex Ginibre ensemble we derived earlier in Cipolloni et al. (Prob Math Phys 1:101–146, 2020). On the level of the one-point function of the low lying singular values we thus confirm the transition from real to complex Ginibre ensembles as the shift parameter z becomes genuinely complex; the analogous phenomenon has been well known for eigenvalues. We use the superbosonization formula (Littelmann et al. in Comm Math Phys 283:343–395, 2008) in a regime where the main contribution comes from a three dimensional saddle manifold.}, author = {Cipolloni, Giorgio and Erdös, László and Schröder, Dominik J}, issn = {1424-0661}, journal = {Annales Henri Poincaré}, keywords = {Mathematical Physics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics}, number = {11}, pages = {3981--4002}, publisher = {Springer Nature}, title = {{Density of small singular values of the shifted real Ginibre ensemble}}, doi = {10.1007/s00023-022-01188-8}, volume = {23}, year = {2022}, } @article{8407, author = {Schanda, Paul}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, pages = {180--186}, publisher = {Elsevier}, title = {{Relaxing with liquids and solids – A perspective on biomolecular dynamics}}, doi = {10.1016/j.jmr.2019.07.025}, volume = {306}, year = {2019}, } @article{8447, abstract = {Solid-state NMR spectroscopy can provide site-resolved information about protein dynamics over many time scales. Here we combine protein deuteration, fast magic-angle spinning (~45–60 kHz) and proton detection to study dynamics of ubiquitin in microcrystals, and in particular a mutant in a region that undergoes microsecond motions in a β-turn region in the wild-type protein. We use 15N R1ρ relaxation measurements as a function of the radio-frequency (RF) field strength, i.e. relaxation dispersion, to probe how the G53A mutation alters these dynamics. We report a population-inversion of conformational states: the conformation that in the wild-type protein is populated only sparsely becomes the predominant state. We furthermore explore the potential to use amide-1H R1ρ relaxation to obtain insight into dynamics. We show that while quantitative interpretation of 1H relaxation remains beyond reach under the experimental conditions, due to coherent contributions to decay, one may extract qualitative information about flexibility.}, author = {Gauto, Diego F. and Hessel, Audrey and Rovó, Petra and Kurauskas, Vilius and Linser, Rasmus and Schanda, Paul}, issn = {0926-2040}, journal = {Solid State Nuclear Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Instrumentation, General Chemistry, Radiation}, number = {10}, pages = {86--95}, publisher = {Elsevier}, title = {{Protein conformational dynamics studied by 15N and 1HR1ρ relaxation dispersion: Application to wild-type and G53A ubiquitin crystals}}, doi = {10.1016/j.ssnmr.2017.04.002}, volume = {87}, year = {2017}, } @article{8448, abstract = {We present an improved fast mixing device based on the rapid mixing of two solutions inside the NMR probe, as originally proposed by Hore and coworkers (J. Am. Chem. Soc. 125 (2003) 12484–12492). Such a device is important for off-equilibrium studies of molecular kinetics by multidimensional real-time NMR spectrsocopy. The novelty of this device is that it allows removing the injector from the NMR detection volume after mixing, and thus provides good magnetic field homogeneity independently of the initial sample volume placed in the NMR probe. The apparatus is simple to build, inexpensive, and can be used without any hardware modification on any type of liquid-state NMR spectrometer. We demonstrate the performance of our fast mixing device in terms of improved magnetic field homogeneity, and show an application to the study of protein folding and the structural characterization of transiently populated folding intermediates.}, author = {Franco, Rémi and Favier, Adrien and Schanda, Paul and Brutscher, Bernhard}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, number = {8}, pages = {125--129}, publisher = {Elsevier}, title = {{Optimized fast mixing device for real-time NMR applications}}, doi = {10.1016/j.jmr.2017.05.016}, volume = {281}, year = {2017}, } @article{8469, abstract = {The accurate experimental determination of dipolar-coupling constants for one-bond heteronuclear dipolar couplings in solids is a key for the quantification of the amplitudes of motional processes. Averaging of the dipolar coupling reports on motions on time scales up to the inverse of the coupling constant, in our case tens of microseconds. Combining dipolar-coupling derived order parameters that characterize the amplitudes of the motion with relaxation data leads to a more precise characterization of the dynamical parameters and helps to disentangle the amplitudes and the time scales of the motional processes, which impact relaxation rates in a highly correlated way. Here. we describe and characterize an improved experimental protocol – based on REDOR – to measure these couplings in perdeuterated proteins with a reduced sensitivity to experimental missettings. Because such effects are presently the dominant source of systematic errors in experimental dipolar-coupling measurements, these compensated experiments should help to significantly improve the precision of such data. A detailed comparison with other commonly used pulse sequences (T-MREV, phase-inverted CP,R18 5/2, and R18 7/1) is provided.}, author = {Schanda, Paul and Meier, Beat H. and Ernst, Matthias}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, number = {2}, pages = {246--259}, publisher = {Elsevier}, title = {{Accurate measurement of one-bond H–X heteronuclear dipolar couplings in MAS solid-state NMR}}, doi = {10.1016/j.jmr.2011.03.015}, volume = {210}, year = {2011}, } @article{8482, abstract = {The SOFAST-HMQC experiment [P. Schanda, B. Brutscher, Very fast two-dimensional NMR spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds, J. Am. Chem. Soc. 127 (2005) 8014–8015] allows recording two-dimensional correlation spectra of macromolecules such as proteins in only a few seconds acquisition time. To achieve the highest possible sensitivity, SOFAST-HMQC experiments are preferably performed on high-field NMR spectrometers equipped with cryogenically cooled probes. The duty cycle of over 80% in fast-pulsing SOFAST-HMQC experiments, however, may cause problems when using a cryogenic probe. Here we introduce SE-IPAP-SOFAST-HMQC, a new pulse sequence that provides comparable sensitivity to standard SOFAST-HMQC, while avoiding heteronuclear decoupling during 1H detection, and thus significantly reducing the radiofrequency load of the probe during the experiment. The experiment is also attractive for fast and sensitive measurement of heteronuclear one-bond spin coupling constants.}, author = {Kern, Thomas and Schanda, Paul and Brutscher, Bernhard}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, number = {2}, pages = {333--338}, publisher = {Elsevier}, title = {{Sensitivity-enhanced IPAP-SOFAST-HMQC for fast-pulsing 2D NMR with reduced radiofrequency load}}, doi = {10.1016/j.jmr.2007.11.015}, volume = {190}, year = {2008}, } @article{8490, abstract = {We demonstrate the feasibility of recording 1H–15N correlation spectra of proteins in only one second of acquisition time. The experiment combines recently proposed SOFAST-HMQC with Hadamard-type 15N frequency encoding. This allows site-resolved real-time NMR studies of kinetic processes in proteins with an increased time resolution. The sensitivity of the experiment is sufficient to be applicable to a wide range of molecular systems available at millimolar concentration on a high magnetic field spectrometer.}, author = {Schanda, Paul and Brutscher, Bernhard}, issn = {1090-7807}, journal = {Journal of Magnetic Resonance}, keywords = {Nuclear and High Energy Physics, Biophysics, Biochemistry, Condensed Matter Physics}, number = {2}, pages = {334--339}, publisher = {Elsevier}, title = {{Hadamard frequency-encoded SOFAST-HMQC for ultrafast two-dimensional protein NMR}}, doi = {10.1016/j.jmr.2005.10.007}, volume = {178}, year = {2006}, }