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The temperature dependence of electron spin coherence in singly negatively charged (In,Ga)As/GaAs quantum dots is studied by time-resolved Faraday rotation. The decoherence time T2 is constant on a microsecond scale for temperatures below…

Materials Science · Physics 2008-07-14 F. G. G. Hernandez , A. Greilich , F. Brito , M. Wiemann , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer

We determine the ortho/para ratios of NH2D and NHD2 in two dense, starless cores, where their formation is supposed to be dominated by gas-phase reactions, which, in turn, is predicted to result in deviations from the statistical spin…

We study theoretically the formation of the nuclear-spin polaron state in semiconductor nanosystems within the Lindblad equation approach. To this end, we derive a general Lindblad equation for the density operator that complies with the…

Mesoscale and Nanoscale Physics · Physics 2022-06-01 Iris Kleinjohann , Andreas Fischer , Mikhail M. Glazov , Frithjof B. Anders

Optical spin pumping of color centers in diamond is presently attracting broad interest as a platform for dynamic nuclear polarization at room temperature, but the mechanisms involved in the generation and transport of polarization within…

We mapped the kinetic temperature structure of the Orion molecular cloud 1 with para-H2CO(303-202, 322-221, and 321-220) using the APEX 12m telescope. This is compared with the temperatures derived from the ratio of the NH3(2,2)/(1,1)…

Astrophysics of Galaxies · Physics 2017-12-27 X. D. Tang , C. Henkel , K. M. Menten , F. Wyrowski , N. Brinkmann , X. W. Zheng , Y. Gong , Y. X. Lin , J. Esimbek , J. J. Zhou , Y. Yuan , D. L. Li , Y. X. He

The loss of information about the relative phase between two quantum states, known as decoherence, strongly limits resolution in electron paramagnetic spectroscopy and hampers the use of molecules for quantum information processing. At low…

Quantum Physics · Physics 2025-04-28 Conor Ryan , Valerio Briganti , Cathal Hogan , Mark O'Neill , Alessandro Lunghi

We determined the ortho/para (o/p) ratios of NH2D and NHD2 in the archetypical pre-stellar core L1544. The core was observed in the two lowest rotational lines of ortho- and para-NH2D using the APEX and the IRAM 30 m telescopes. The…

We compute the rotational quenching rates of the first 81 rotational levels of ortho- and para-H2CO in collision with ortho- and para-H2, for a temperature range of 10-300 K. We make use of the quantum close-coupling and coupled-states…

Solar and Stellar Astrophysics · Physics 2015-06-15 Laurent Wiesenfeld , Alexandre Faure

The spin temperature of neutral hydrogen, which determines the optical depth and brightness of the 21 cm line, is determined by the competition between radiative and collisional processes. Here we examine the role of proton-hydrogen…

Astrophysics · Physics 2008-11-26 Steven Furlanetto , Michael Furlanetto

For a general understanding of the physics involved in the star formation process, measurements of physical parameters such as temperature and density are indispensable. The chemical and physical properties of dense clumps of molecular…

Astrophysics of Galaxies · Physics 2017-02-01 X. D. Tang , C. Henkel , K. M. Menten , X. W. Zheng , J. Esimbek , J. J. Zhou , C. C. Yeh , C. König , Y. Yuan , Y. X. He , D. L. Li

Layered Co oxide NaxCoO2.yH2O with a superconducting transition temperature Tc =4.5 K has been studied by 59Co NQR. The nuclear spin relaxation rate 1/59T1 is nearly proportional to temperature T in the normal state. In the superconducting…

Superconductivity · Physics 2009-11-10 Yoshiaki Kobayashi , Mai Yokoi , Masatoshi Sato

In this paper, we investigate the liquid gas phase transition for the spin polarized nuclear matter. Applying the lowest order constrained variational (LOCV) method, and using two microscopic potentials, $AV_{18}$ and $UV_{14}$+TNI, we…

Nuclear Theory · Physics 2015-09-29 Z. Rezaei , M. Bigdeli , G. H. Bordbar

The magnetic and structural transformations in the nickel crystal within the temperature range 470 < T< 631 K is studied on the basis of general phenomenological theory of spin-orbit phase transitions. A new phase transition at Tls \approx…

Strongly Correlated Electrons · Physics 2012-07-05 Khisa Sh. Borlakov , Albert Kh. Borlakov

The problem of the nuclear spin-lattice relaxation in La$_2$CuO$_4$ is revisited in connection with the recent measurements of the NQR relaxation rate for temperatures up to $ 900\mbox{K} $ [T.\ Imai {\em et al.}, Phys.\ Rev.\ Lett., in…

Condensed Matter · Physics 2009-10-22 A. Sokol , E. Gagliano , S. Bacci

Formaldehyde (H$_2$CO) is an important precursor to organics like methanol (CH$_3$OH). It is important to understand the conditions that produce H$_2$CO and prebiotic molecules during star and planet formation. H$_2$CO possesses both…

We present precision spectroscopy on electrically trapped formaldehyde (H$_2$CO), demonstrating key attributes which will enable molecular spectroscopy with unprecedented precision. Our method makes use of a microstructured electric trap…

Atomic Physics · Physics 2018-07-19 Alexander Prehn , Martin Ibrügger , Gerhard Rempe , Martin Zeppenfeld

Using soft x-ray absorption spectroscopy and magnetic circular dichroism at the Co-$L_{2,3}$ edge we reveal that the spin state transition in LaCoO$_{3}$ can be well described by a low-spin ground state and a triply-degenerate high-spin…

The spin-lattice relaxation rate $1/T_1$ and the spin echo decay rate $1/T_{2G}$ for the spin-$1\over 2$ antiferromagnetic Heisenberg chain are calculated using quantum Monte Carlo and maximum entropy analytic continuation. The results are…

Condensed Matter · Physics 2009-10-28 Anders W. Sandvik

The spin temperature of neutral hydrogen, which determines the 21 cm optical depth and brightness temperature, is set by the competition between radiative and collisional processes. In the high-redshift intergalactic medium, the dominant…

Astrophysics · Physics 2008-11-26 Steven Furlanetto , Michael Furlanetto

The first experimental study of the low-temperature kinetics of the gas-phase reaction of NH2 with formaldehyde (CH2O) has been performed. This reaction has previously been suggested as a source of formamide (NH2CHO) in interstellar…

Astrophysics of Galaxies · Physics 2022-10-05 Kevin M. Douglas , Daniel Lucas , Catherine Walsh , Niclas A. West , Mark A. Blitz , Dwayne E. Heard