共查询到20条相似文献,搜索用时 15 毫秒
1.
In this work we consider the entropy-corrected version of interacting holographic dark energy (HDE), in the non-flat universe
enclosed by apparent horizon. Two corrections of entropy so-called logarithmic ‘LEC’ and power-law ‘PLEC’ in HDE model with
apparent horizon as an IR-cutoff are studied. The ratio of dark matter to dark energy densities u, equation of state parameter w
D
and deceleration parameter q are obtained. We show that the cosmic coincidence problem is solved for interacting models. By studying the effect of interaction
in EoS parameter of both models, we see that the phantom divide may be crossed and also understand that the interacting models
can drive an acceleration expansion at the present and future, while in non-interacting case, this expansion can happen only
at the early time. The graphs of deceleration parameter for interacting models, show that the present acceleration expansion
is preceded by a sufficiently long period deceleration at past. Moreover, the thermodynamical interpretation of interaction
between LECHDE and dark matter is described. We obtain a relation between the interaction term of dark components and thermal
fluctuation in a non-flat universe, bounded by the apparent horizon. In limiting case, for ordinary HDE, the relation of interaction
term versus thermal fluctuation is also calculated. 相似文献
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3.
In this paper we discuss the Eliashberg equations for the case of an electron-phonon coupling with an energy cutoff. This cutoff is imposed either for the energy difference by means of a strip function, or for both energies, with a Cooper-like expression. The strip function cutoff requires explicit calculation of not only the frequency renormalization functionZ but also the energy renormalizationX. The physical origin of such cutoffs might lie in the very strong electron-electron interaction which seems typical for highT
c
superconductivity. If such cutoffs are admitted, the hypothesis thatT
c
is caused at least in part by a strong electron-phonon interaction can be reconsidered. We find that the combination of strong coupling and low-energy cutoff could produce highT
c
with only small isotope effect and with little damping or pulling of the phonon modes. Correlation with other physical properties, such as specific heat, is reexamined in view to estimate the coupling constant . Some objections to the model using strong electron phonon interaction are removed and better agreement with observed properties is obtained 相似文献
4.
An integrated optical cutoff modulator is fed back electrically. In this way an electrooptical oscillator is built applicable as optical clock generator or electrical switchable oscillator for optical communication systems. Its center frequency is 380 MHz with a stability of 6 × 10-5. The mode structure of the oscillator is investigated. 相似文献
5.
Very long wavelength infrared focal plane arrays with 50% cutoff wavelength based on type-Ⅱ In As/GaSb superlattice 下载免费PDF全文
A very long wavelength infrared(VLWIR) focal plane array based on In As/Ga Sb type-Ⅱ super-lattices is demonstrated on a Ga Sb substrate. A hetero-structure photodiode was grown with a 50% cut-off wavelength of 15.2 μm, at 77 K.A 320×256 VLWIR focal plane array with this design was fabricated and characterized. The peak quantum efficiency without an antireflective coating was 25.74% at the reverse bias voltage of-20 mV, yielding a peak specific detectivity of 5.89×1010cm·Hz~(1/2)·W~(-1). The operability and the uniformity of response were 89% and 83.17%. The noise-equivalent temperature difference at 65 K exhibited a minimum at 21.4 mK, corresponding to an average value of 56.3 mK. 相似文献
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A Lorentz and gauge symmetry preserving regularization method is proposed in 4 dimensions based on a momentum cutoff. We use
the conditions of gauge invariance or equivalently the freedom to shift the loop momentum to define the evaluation of the
terms carrying even number of Lorentz indices, e.g. proportional to k
μ
k
ν
. The remaining scalar integrals are calculated with a four dimensional momentum cutoff. The finite terms (independent of
the cutoff) are free of ambiguities coming from subtractions in non-trivial cases. Finite parts of the result are equal to
that of dimensional regularization. 相似文献
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10.
Ben Heidenreich Matthew Reece Tom Rudelius 《The European Physical Journal C - Particles and Fields》2018,78(4):337
We study ultraviolet cutoffs associated with the Weak Gravity Conjecture (WGC) and Sublattice Weak Gravity Conjecture (sLWGC). There is a magnetic WGC cutoff at the energy scale \(e G_N^{-1/2}\) with an associated sLWGC tower of charged particles. A more fundamental cutoff is the scale at which gravity becomes strong and field theory breaks down entirely. By clarifying the nature of the sLWGC for nonabelian gauge groups we derive a parametric upper bound on this strong gravity scale for arbitrary gauge theories. Intriguingly, we show that in theories approximately saturating the sLWGC, the scales at which loop corrections from the tower of charged particles to the gauge boson and graviton propagators become important are parametrically identical. This suggests a picture in which gauge fields emerge from the quantum gravity scale by integrating out a tower of charged matter fields. We derive a converse statement: if a gauge theory becomes strongly coupled at or below the quantum gravity scale, the WGC follows. We sketch some phenomenological consequences of the UV cutoffs we derive. 相似文献
11.
A. G. U. Perera S. G. Matsik M. B. M. Rinzan A. Weerasekara M. Alevli H. C. Liu M. Buchanan B. Zvonkov V. Gavrilenko 《Infrared Physics & Technology》2003,44(5-6):347-353
Results are presented on the effects of doping variation on the cutoff wavelength (λc) of homojunction interfacial workfunction internal photoemission far infrared detectors. The behavior at low doping (<1019 cm−3) is well predicted by the free carrier absorption model used previously. However at high doping the observed λc is much shorter than the values predicted by the workfunction obtained from Arrhenius plots. An explanation for the reduced λc in the high doping region is presented using a model for depletion of the heavy hole band due to direct transitions from the heavy hole to light hole band. 相似文献
12.
Fetterman MR 《Optics letters》2005,30(17):2311-2313
Infrared derivative spectroscopy is a useful technique for finding peaks hidden in broad spectral features. A data acquisition technique is shown that will improve the signal-to-noise ratio (SNR) of Fourier-transform infrared (FTIR) derivative spectroscopy. Typically, in a FTIR measurement one samples each point for the same time interval. The effect of using a graded time interval is studied. The simulations presented show that the SNR of first-derivative FTIR spectroscopy will improve by 15% and that the SNR of second-derivative FTIR will improve by 34%. 相似文献
13.
The progress in the quantum well infrared photo-detector (QWIP) based on quantum confinement in semiconductor in recent 10
years has been reviewed. The differences between QWIP and the HgCdTe (HCT) infrared detector as well as their compensation
are analyzed. The outlook for near-future trends in QWIP technologies is also presented.
Supported by the National Natural Science Foundation of China (Grant Nos. 10474020, 10734090, and 60221502) and the Key Program
of Basic Research of China (Grant No. 2004CB619004) 相似文献
14.
H. Fraas 《Zeitschrift für Physik A Hadrons and Nuclei》1967,200(4):375-397
A non-local gauge-invariant Lagrangian is given, which describes gauge-invariant quantum electro-dynamics with a modified fermion propagator. Some examples are discussed. 相似文献
15.
We set an upper bound on the gravitational cutoff in theories with exact quantum numbers of large N periodicity, such as Z(N) discrete symmetries. The bound stems from black hole physics. It is similar to the bound appearing in theories with N particle species, though a priori, a large discrete symmetry does not imply a large number of species. Thus, there emerges a potentially wide class of new theories that address the hierarchy problem by lowering the gravitational cutoff due to the existence of large Z(10(32))-type symmetries. 相似文献
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17.
Masaki Hisaka 《Optical Review》2018,25(3):397-402
The techniques for temperature measurement within the human body are important for clinical applications. A method for noncontact local infrared (IR) radiation measurements was investigated deep within an object to simulate how the core human body temperature can be obtained. To isolate the IR light emitted from a specific area within the object from the external noise, the radiating IR light was detected using an IR point detector, which comprises a pinhole and a thermopile positioned at an imaging relation with the region of interest within the object. The structure of the helical filament radiating IR light inside a light bulb was thermally imaged by scanning the bulb in two dimensions. Moreover, this approach was used to effectively measure IR light in the range of human body temperature using a glass plate placed in front of the heat source, mimicking the ocular fundus. 相似文献
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19.
A low-temperature FIR spectrometer was used for measuring EPR of LiHoF4 in the field range 0–7 T, frequency range 150–1600 GHz. Zero field splittings and g-values for the lowest four energy levels are presented. Two sets of hyperfine lines were observed, corresponding to ΔmN = 0 and ΔmN = ?1, each set with line spacings according to . The exchange part of the molecular field constant is determined and compared to results from previous experiments. 相似文献
20.
R. V. Ambartzumian I. N. Knyazev V. V. Lobko G. N. Makarov A. A. Puretzky 《Applied Physics A: Materials Science & Processing》1979,19(1):75-79
Multiple ir photon absorption spectra (MPAS) of OsO4 are obtained in the range of energy fluencies from 3·10−2 to 1.26 J/cm2. A possible interpretation of MPAS is given on the basis of weak forbidden rovibrational transitions. The stepwise character
of the absorption on the laser energy fluence is observed. 相似文献