Low-energy excitation mode

Nowadays it is widely accepted that there should be realized various phases of QCD in temperature (T) - density (ftp,) plane. When we emphasize the low T and high pp region, the subjects are sometimes called physics of high-density QCD. The main purposes in this field should be to figure out the properties of phase transitions and new phases, and to extract their symmetry breaking pattern and low-energy excitation modes there on the basis of QCD. On the other hand, these studies have phenomenological implications on relativistic heavy-ion collisions and compact stars like neutron stars or quark stars. 

It would be important to figure out the low energy excitation modes (Nambu-Goldstone modes) built on the ferromagnetic phase. The spin waves are well known in the Heisenberg model [10]. Then, how about our case [32] ... 

Phonon frequency, E. (cm ), defined as energy difference between the zero-phonon hole and the pseudophone sidehole and the energy for the low-energy excitation mode obtained from heat capacity measurements, E. (cm ... 

Photochemical hole burning spectroscopy is applied to estimate the low-temperature relaxation properties of polymers. Methacrylate polymers, polyethylene derivatives, and polymers with aromatic groups were studied. Both slight and large changes of microenvironments around doped dye molecules are detected by temperature cycling experiment. Relaxation behavior of the polymers is discussed in relation to their diemical structures. The low-energy excitation mode of each polymer is also estimated and... 

We discuss the obtained low-energy excitation modes of the polymers from the aspect of their chemical structures and relaxation properties. 

Estimation of Low-Energy Excitation Modes. An absorption line profile of each dye molecule at low temperature consists of two components a sharp zero-phonon line and a broad phonon side band. Tbe energy difference between the zero-phonon line and the phonon side band coincides with the low-energy excitation mode or phonon frequency of the matrix when multi-phonon processes can be ignored. 

Figure 11 shows a saturated hole proffle burned to estimate the low-energy excitation mode, E of TPP/PnPMA. A deep zero-phonon hole is created at 644.8 nm. In addition, there are two broad holes at bodi sides of the zero-phonon hole. The broad hole at the shorter wavelength is called a phonon side hole and the one at the longer wavelength is called a pseudo-phonon side hole . The phonon side hole consists of a phonon side band of the zero-phonon hole, and the p udo-phonon side hole is made of the zero-phonon line of the reacted molecules which have been excited via phonon side band. 

Pelletier and Reber315 present new luminescence and low-energy excitation spectra of Pd(SCN)42 in three different crystalline environments, K2Pd(SCN)4, [K(18-crown-6)]2Pd(SCN)4, and (2-diethylammonium A -(2,6-dimethylphcnyl)acetamide)2Pd(SCN)4, and analyze the vibronic structure of the luminescence spectra, their intensities, and lifetimes as a function of temperature. The spectroscopic results are compared to the HOMO and LUMO orbitals obtained from density functional calculations to qualitatively illustrate the importance of the bending modes in the vibronic structure of the luminescence spectra. 

Characteristic Decomposition Modes of the Low-Energy Excited Aikane Moiecuies... 

The low energy excitation is observed at finite frequencies only for T In moderate magnetic fields its frequency is increasing as shown in Fig. 2d). Such a shift of the low temperature mode and the order parameter-like dependence on temperature has been taken as evidence that the mode cannot be related to a singlet state and must be identified as a longitudinal magnon [33, 34],... 

According to the selection rules, the HRS spectroscopy can in principle be used as an alternative for IR spectroscopy [19]. Indeed, this nonlinear spectroscopy has several advantages IR-mode detection is possible even in IR-opaque media and its spatial resolution is much better than IR microscopy. Moreover, HRS signals appear in the doubled frequency region, which is far from the intense excitation laser line, and hence, low-energy vibration modes are easily observable. 

A peculiar feature of Bose condensates and superfluids is that their low-energy excitations correspond to collective modes, which can be described as fluctuations of the order parameter [106]. For uniform dilute boson gases, with an effective interparticle interaction potential F(r — r ) = g8(r — r ), where g = Anfisa/m is the coupling constant, the excitations (characterized by energies e (fe)) are given by the Bogoliobov spectrum [136]... 

Other qualitative rules for the study of reaction paths have been derived independently. For unimolecular reactions, it has been found that conditions favorable to a given path exist if there is a low-energy excited state of the same symmetry as the normal mode corresponding to the reaction coordinate, the transition density is localized in the region of nuclear motion and the excitation energy decreases along the coordinate 32>. 

Coherent neutron inelastic scattering (CNIS) is the only technique by which fundamental vibrations with q 0 can be observed. The energy dependence of the neutron scattering cross-section limits, in general, the usefulness of CNIS to low-energy excitations (i.e., external modes). 

Figure 10-15. Output vs. input energy characteristic of our laser device. The horizontal dashed curve indicates the zero line. A clear laser threshold behavior at an excitation pulse energy ol 1.5 nJ is observed. Below the lasing threshold only isotropic phololuminesccncc is entitled. Above threshold the device emits low divergence single mode laser emission perpendicular to the surface, as schematically shown in the inset. The laser light is polarized parallel to the grating lines.

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