In this paper, a new version of the interacting model of new agegraphic dark energy （INADE） is proposed and analyzed in detail. The interaction between dark energy and dark matter is reconsidered. The interaction te...In this paper, a new version of the interacting model of new agegraphic dark energy （INADE） is proposed and analyzed in detail. The interaction between dark energy and dark matter is reconsidered. The interaction term Q = bh0ραdcρ1-α dm is adopted, which abandons the Hubble expansion rate H and involves both Pae and Pare. Moreover, the new initial condition for the agegraphie dark energy is used, which solves the problem of accommodating baryon matter and radiation in the model. The solution of the model can be given using an iterative algorithm. A concrete example for the calculation of the model is given. Furthermore, the model is constrained by using the combined Planck data （Planck＋BAO＋SNIa＋H0） and the combined WMAP-9 data （WMAP＋BAO＋SNIa＋H0）. Three typical cases are considered： （A） Q = bHoPde, （B） Q = bHo√ρdeρdm,and （C） Q = bHopdm, which correspond to α = 1, 1/2, and 0, respectively. The departures of the models from the ACDM model are measured by the ABIC and AAIC values. It is shown that the INADE model is better than the NADE model in the fit, and the 1NADE（A） model is the best in fitting data among the three cases.展开更多
Strong lensing is an effective way to probing the properties of dark energy.In this paper,we use the strong lensing data to constrain the f(T)theory,which is a new modified gravity to explain the present accelerating ...Strong lensing is an effective way to probing the properties of dark energy.In this paper,we use the strong lensing data to constrain the f(T)theory,which is a new modified gravity to explain the present accelerating cosmic expansion without the need of dark energy.In our discussion,the CMB and BAO data are also added to constrain model parameters tightly and three different f(T)models are studied.We find that strong lensing has an important role on constraining f(T)models,and once the CMB+BAO data is added,a tighter constraint is obtained.However,the consistency of our result with what is obtained from SNIa+CMB+BAO is actually model-dependent.展开更多
Cosmic inflation is considered assuming a cosmologically varying Newtonian gravitational constant, <em>G.</em> Utilizing two specific models for, <em>G</em><sup>-1</sup>(a), where, ...Cosmic inflation is considered assuming a cosmologically varying Newtonian gravitational constant, <em>G.</em> Utilizing two specific models for, <em>G</em><sup>-1</sup>(a), where, a, is the cosmic scale parameter, we find that the Hubble parameter, <em>H</em>, at inception of <em style="white-space:normal;">G</em><sup style="white-space:normal;">-1</sup>, may be as high as 7.56 E53 km/(s Mpc) for model A, or, 8.55 E53 km/(s Mpc) for model B, making these good candidates for inflation. The Hubble parameter is inextricably linked to <em>G</em> by Friedmanns’ equation, and if <em>G</em> did not exist prior to an inception temperature, then neither did expansion. The CBR temperatures at inception of <em style="white-space:normal;">G</em><sup style="white-space:normal;">-1</sup> are estimated to equal, 6.20 E21 Kelvin for model A, and 7.01 E21 for model B, somewhat lower than CBR temperatures usually associated with inflation. These temperatures would fix the size of Lemaitre universe in the vicinity of 3% of the Earths’ radius at the beginning of expansion, thus avoiding a singularity, as is the case in the ΛCDM model. In the later universe, a variable<em> G </em>model cannot be dismissed based on SNIa events. In fact, there is now some compelling astronomical evidence, using rise times and luminosity, which we discuss, where it could be argued that SNIa events can only be used as good standard candles if a variation in <em>G</em> is taken into account. Dark energy may have more to do with a weakening <em>G</em> with increasing cosmological time, versus an unanticipated acceleration of the universe, in the late stage of cosmic evolution.展开更多
We explore the theoretical possibility that dark energy density is derived from massless scalar bosons in vacuum and present a physical model for dark energy. By assuming massless scalar bosons fall into the horizon b...We explore the theoretical possibility that dark energy density is derived from massless scalar bosons in vacuum and present a physical model for dark energy. By assuming massless scalar bosons fall into the horizon boundary of the cosmos with the expansion of the universe, we can deduce the uncertainty in the relative position of scalar bosons based on the quantum fluctuation of space-time and the assumption that scalar bosons satisfy P-symmetry under the parity transformation Pφ(r) =-φ(r), which can be used to estimate scalar bosons and dark energy density. Furthermore, we attempt to explain the origin of negative pressure from the increasing entropy density of the Boltzmann system and derive the equation for the state parameter, which is consistent with the specific equations of state for dark energy. Finally, we employ the SNIa Pantheon sample and Planck 2018 CMB angular power spectra to constrain the models and provide statistical results for the cosmology parameters.展开更多
联想存储正式加盟全球网络存储工业协会（中国）（Storage Networking Industry Association China简称SNIA—CHINA）．担纲SNIA-China会员委员会首届主席。此次联想（存储）的加入．旨在通过对国外先进存储技术的引入学习，推动中国存...联想存储正式加盟全球网络存储工业协会（中国）（Storage Networking Industry Association China简称SNIA—CHINA）．担纲SNIA-China会员委员会首届主席。此次联想（存储）的加入．旨在通过对国外先进存储技术的引入学习，推动中国存储技术行业新标准的确立．带给中国真正的国际存储时代。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.10975032 and 11175042)the National Ministry of Education of China(Grants Nos.NCET-09-0276,N110405011 and N120505003)the Provincial Department of Education of Liaoning(Grant No.L2012087)
文摘In this paper, a new version of the interacting model of new agegraphic dark energy （INADE） is proposed and analyzed in detail. The interaction between dark energy and dark matter is reconsidered. The interaction term Q = bh0ραdcρ1-α dm is adopted, which abandons the Hubble expansion rate H and involves both Pae and Pare. Moreover, the new initial condition for the agegraphie dark energy is used, which solves the problem of accommodating baryon matter and radiation in the model. The solution of the model can be given using an iterative algorithm. A concrete example for the calculation of the model is given. Furthermore, the model is constrained by using the combined Planck data （Planck＋BAO＋SNIa＋H0） and the combined WMAP-9 data （WMAP＋BAO＋SNIa＋H0）. Three typical cases are considered： （A） Q = bHoPde, （B） Q = bHo√ρdeρdm,and （C） Q = bHopdm, which correspond to α = 1, 1/2, and 0, respectively. The departures of the models from the ACDM model are measured by the ABIC and AAIC values. It is shown that the INADE model is better than the NADE model in the fit, and the 1NADE（A） model is the best in fitting data among the three cases.
基金supported by the National Natural Science Foundation of China(Grant Nos.10935013,11175093,11222545 and 11075083)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.Z6100077 and R6110518)+3 种基金the National Basic Research Program of China(Grant No.2010CB832803)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT0964)the Hunan Provincial Natural Science Foundation of China(Grant No.11JJ7001)the Program for the Key Discipline in Hunan Province
文摘Strong lensing is an effective way to probing the properties of dark energy.In this paper,we use the strong lensing data to constrain the f(T)theory,which is a new modified gravity to explain the present accelerating cosmic expansion without the need of dark energy.In our discussion,the CMB and BAO data are also added to constrain model parameters tightly and three different f(T)models are studied.We find that strong lensing has an important role on constraining f(T)models,and once the CMB+BAO data is added,a tighter constraint is obtained.However,the consistency of our result with what is obtained from SNIa+CMB+BAO is actually model-dependent.
文摘Cosmic inflation is considered assuming a cosmologically varying Newtonian gravitational constant, <em>G.</em> Utilizing two specific models for, <em>G</em><sup>-1</sup>(a), where, a, is the cosmic scale parameter, we find that the Hubble parameter, <em>H</em>, at inception of <em style="white-space:normal;">G</em><sup style="white-space:normal;">-1</sup>, may be as high as 7.56 E53 km/(s Mpc) for model A, or, 8.55 E53 km/(s Mpc) for model B, making these good candidates for inflation. The Hubble parameter is inextricably linked to <em>G</em> by Friedmanns’ equation, and if <em>G</em> did not exist prior to an inception temperature, then neither did expansion. The CBR temperatures at inception of <em style="white-space:normal;">G</em><sup style="white-space:normal;">-1</sup> are estimated to equal, 6.20 E21 Kelvin for model A, and 7.01 E21 for model B, somewhat lower than CBR temperatures usually associated with inflation. These temperatures would fix the size of Lemaitre universe in the vicinity of 3% of the Earths’ radius at the beginning of expansion, thus avoiding a singularity, as is the case in the ΛCDM model. In the later universe, a variable<em> G </em>model cannot be dismissed based on SNIa events. In fact, there is now some compelling astronomical evidence, using rise times and luminosity, which we discuss, where it could be argued that SNIa events can only be used as good standard candles if a variation in <em>G</em> is taken into account. Dark energy may have more to do with a weakening <em>G</em> with increasing cosmological time, versus an unanticipated acceleration of the universe, in the late stage of cosmic evolution.
基金Supported by Xiaofeng Yang’s Xinjiang Tianchi Bairen project and CAS Pioneer Hundred Talents Programpartly supported by the National Key R&D Program of China (2018YFA0404602)
文摘We explore the theoretical possibility that dark energy density is derived from massless scalar bosons in vacuum and present a physical model for dark energy. By assuming massless scalar bosons fall into the horizon boundary of the cosmos with the expansion of the universe, we can deduce the uncertainty in the relative position of scalar bosons based on the quantum fluctuation of space-time and the assumption that scalar bosons satisfy P-symmetry under the parity transformation Pφ(r) =-φ(r), which can be used to estimate scalar bosons and dark energy density. Furthermore, we attempt to explain the origin of negative pressure from the increasing entropy density of the Boltzmann system and derive the equation for the state parameter, which is consistent with the specific equations of state for dark energy. Finally, we employ the SNIa Pantheon sample and Planck 2018 CMB angular power spectra to constrain the models and provide statistical results for the cosmology parameters.
文摘联想存储正式加盟全球网络存储工业协会（中国）（Storage Networking Industry Association China简称SNIA—CHINA）．担纲SNIA-China会员委员会首届主席。此次联想（存储）的加入．旨在通过对国外先进存储技术的引入学习，推动中国存储技术行业新标准的确立．带给中国真正的国际存储时代。
