By studying the Gödel-type solution,the causality in f(R)gravity with an arbitrary coupling between matter and geometry is discussed.Assuming that the matter source is a perfect fluid and a scalar field,respectiv...By studying the Gödel-type solution,the causality in f(R)gravity with an arbitrary coupling between matter and geometry is discussed.Assuming that the matter source is a perfect fluid and a scalar field,respectively,we find that for the perfect fluid case,noncausal Gödel−type solutions exist and there is a critical radius rc beyond which the causality is violated.For the scalar field case,the violation of causality is forbidden.展开更多
We calculate the energy level shift of a static ground state two-level atom interacting with fluctuating massless scalar fields in the Hartle–Hawking vacuum outside a Schwarzschild black hole.It is found that the ene...We calculate the energy level shift of a static ground state two-level atom interacting with fluctuating massless scalar fields in the Hartle–Hawking vacuum outside a Schwarzschild black hole.It is found that the energy level shift is position-dependent and gives rise to a force on the atom besides the classical gravitational force.This force behaves like r^(-1)(r-2M)^(-1) for r approaching 2M,whereas it behaves like r^(-2) for large r.展开更多
Observations show that Type Ia supernovae （SNe Ia） are dimmer than ex- pected from a matter dominated Universe. It has been suggested that this observed phenomenon can also be explained using light absorption instea...Observations show that Type Ia supernovae （SNe Ia） are dimmer than ex- pected from a matter dominated Universe. It has been suggested that this observed phenomenon can also be explained using light absorption instead of dark energy. However, there is a serious degeneracy between the cosmic absorption parameter and the present matter density parameter Ωm when one tries to place constraints on the cosmic opacity using SNe Ia data. We combine the latest baryon acoustic oscillation （BAO） and Union2 SNe Ia data in order to break this degeneracy. Assuming a fiat ACDM model, we find that, although an opaque Universe is favored by SNe Ia＋BAO since the best fit value of the cosmic absorption parameter is larger than zero, fire = 1 is ruled out at the 99.7% confidence level. Thus, cosmic opacity is not sufficient to account for the present observations and dark energy or modified gravity is still re- quired.展开更多
We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the s...We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the spherical β model）, and the luminosity distance DL from Constitution and Union2 type Ia supernova （SNe Ia） datasets. To obtain DL associated with the observed DA at the same redshift, we smooth the noise of the SNe Ia in a model-independent way, obtain the evolutionary curve of DL and, finally, test the DD relation. We find that the elliptical β model, when compared with the SNe Ia from the Constitution compilation, is only consistent with the DD relation at the 3σ confidence level （CL）, while the spherical β model is incompatible with the DD relation at the 3σ CL. For the Union2 compilation, the De Filippis and Bonamente samples are marginally compatible with the validity of the DD relation at the 1σ and 2σ CLs, respectively.展开更多
The nonlocal symmetries of the Burgers equation are explicitly given by the truncated Painlevé method.The auto-B?cklund transformation and group invariant solutions are obtained via the localization procedure for...The nonlocal symmetries of the Burgers equation are explicitly given by the truncated Painlevé method.The auto-B?cklund transformation and group invariant solutions are obtained via the localization procedure for the nonlocal residual symmetries. Furthermore, the interaction solutions of the solition-Kummer waves and the solition-Airy waves are obtained.展开更多
We study the Alice-Bob peakon system generated from an integrable peakon system using the strategy of the so- called Alice-Bob non-local KdV approach [Scientific Reports 7 （2017） 869]. Nonlocal integrable peakon equ...We study the Alice-Bob peakon system generated from an integrable peakon system using the strategy of the so- called Alice-Bob non-local KdV approach [Scientific Reports 7 （2017） 869]. Nonlocal integrable peakon equations are obtained and shown to have peakon solutions.展开更多
There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia super...There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia supernova （SNe Ia）. Here, we show that the tension can be alleviated, if we first calibrate, with the help of the distance-duality relation, the light-curve fitting parameters in the distance estimation in SNe Ia observations with the angular diameter distance data of the galaxy clusters and then re-estimate the distances for the SNe Ia with the corrected fitting parameters. This was used to explore their cosmological implications in the context of the spatially fiat cosmology. We find a higher value for the matter density parameter, Ωm, as compared to that from the original SNLS3, which is in agreement with Planck observations at 68.3% confidence. Therefore, the tension between Planck measurements and SNe Ia observations regarding Ωm can be effectively alleviated without invoking new physics or resorting to extensions for the standard concordance model. Moreover, with the absolute magnitude of a fiducial SNe Ia, M, determined first, we obtained a constraint on the Hubble constant with SNLS3 alone, which is also consistent with Planck.展开更多
A special integrable nonlocal nonlinear Schroodinger equation, NNLS, or namely Alice-Bob NLS（ABNLS）equation is investigated. By means of the general N-th Darboux transformation, one can get various interesting solut...A special integrable nonlocal nonlinear Schroodinger equation, NNLS, or namely Alice-Bob NLS（ABNLS）equation is investigated. By means of the general N-th Darboux transformation, one can get various interesting solutions to display different types of structures especially for solitons. By using the Darboux transformation, its soliton solutions are obtained. Finally, by adjusting the values of free parameters, different kinds of solutions such as kinks, complexitons and rogue-wave solutions are explicitly exhibited. It is found that these solutions are quite different from the ones of the classical NLS equation.展开更多
The symmetry of the fermionic field is obtained by means of the Lax pair of the mKdV equation. A new super mKdV equation is constructed by virtue of the symmetry of the fermionic form. The super mKdV system is changed...The symmetry of the fermionic field is obtained by means of the Lax pair of the mKdV equation. A new super mKdV equation is constructed by virtue of the symmetry of the fermionic form. The super mKdV system is changed to a system of coupled bosonic equations with the bosonization approach. The bosonized SmKdV(BSmKdV)equation admits Painlevé property by the standard singularity analysis. The traveling wave solutions of the BSmKdV system are presented by the mapping and deformation method. We also provide other ideas to construct new super integrable systems.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
By using type Ia supernovae （SNIa） to provide the luminosity distance （LD） directly, which depends on the value of the Hubble constant H0 = 100h km·s^-1· Mpc^-1, and the angular diameter distance from ga...By using type Ia supernovae （SNIa） to provide the luminosity distance （LD） directly, which depends on the value of the Hubble constant H0 = 100h km·s^-1· Mpc^-1, and the angular diameter distance from galaxy clusters or baryon acoustic oscillations （BAOs） to give the derived LD according to the distance duality relation, we propose a model-independent method to determine h from the fact that different observations should give the same LD at a given redshift. Combining the Sloan Digital Sky Survey II （SDSS-II） SNIa from the MLCS2k2 light curve fit and galaxy cluster data, we find that at the 1σ confidence level （CL）, h = 0.5867±0.0303 for the sample of the elliptical β model for galaxy clusters, and h = 0.6199± 0.0293 for that of the spherical β model. The former is smaller than the values from other observations, whereas the latter is consistent with the Planck result at the 2σ CL and agrees very well with the value reconstructed directly from the H（z） data. With the SDSS-II SNIa and BAO measurements, a tighter constraint, h = 0.6683 ± 0.0221, is obtained. For comparison, we also consider the Union 2.1 SNIa from the SALT2 light curve fitting. The results from the Union 2.1 SNIa are slightly larger than those from the SDSS-II SNIa, and the Union 2.1 SNIa ＋ BAOs give the tightest value. We find that the values from SNIa ＋ BAOs are quite consistent with those from the Planck and the BAOs, as well as the local measurement from Cepheids and very-low-redshift SNIa.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10935013,11175093 and 11075083the Zhejiang-Provincial Natural Science Foundation of China under Grant Nos Z6100077 and R6110518+4 种基金the FANEDD under Grant No 200922the National Basic Research Program of China under Grant No 2010CB832803the NCET under Grant No 09-0144the PCSIRT under Grant No IRT0964the Hunan-Provincial Natural Science Foundation of China under Grant No 11JJ7001.
文摘By studying the Gödel-type solution,the causality in f(R)gravity with an arbitrary coupling between matter and geometry is discussed.Assuming that the matter source is a perfect fluid and a scalar field,respectively,we find that for the perfect fluid case,noncausal Gödel−type solutions exist and there is a critical radius rc beyond which the causality is violated.For the scalar field case,the violation of causality is forbidden.
基金Supported in part by the National Natural Science Foundation of China under Grants Nos 11075083,11005038 and 10935013the Zhejiang Provincial Natural Science Foundation of China under Grant No Z6100077+2 种基金the National Basic Research Program of China under Grant No 2010CB832803the PCSIRT under Grant No IRT0964the Hunan Provincial Natural Science Foundation of China under Grant No 11JJ7001.
文摘We calculate the energy level shift of a static ground state two-level atom interacting with fluctuating massless scalar fields in the Hartle–Hawking vacuum outside a Schwarzschild black hole.It is found that the energy level shift is position-dependent and gives rise to a force on the atom besides the classical gravitational force.This force behaves like r^(-1)(r-2M)^(-1) for r approaching 2M,whereas it behaves like r^(-2) for large r.
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)+6 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of PR China (FANEDD, Grant No. 200922)the National Basic Research Program of China (973 program, Grant No. 2010CB832803)the Program for New Century Excellent Talents in University (NCET, Grant No. 09-0144)the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT, Grant No. IRT0964)Hunan Provincial Natural Science Foundation of China (Grant No. 11JJ7001)the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP, Grant No. 20124306110001)the Program for the Key Discipline in Hunan Province
文摘Observations show that Type Ia supernovae （SNe Ia） are dimmer than ex- pected from a matter dominated Universe. It has been suggested that this observed phenomenon can also be explained using light absorption instead of dark energy. However, there is a serious degeneracy between the cosmic absorption parameter and the present matter density parameter Ωm when one tries to place constraints on the cosmic opacity using SNe Ia data. We combine the latest baryon acoustic oscillation （BAO） and Union2 SNe Ia data in order to break this degeneracy. Assuming a fiat ACDM model, we find that, although an opaque Universe is favored by SNe Ia＋BAO since the best fit value of the cosmic absorption parameter is larger than zero, fire = 1 is ruled out at the 99.7% confidence level. Thus, cosmic opacity is not sufficient to account for the present observations and dark energy or modified gravity is still re- quired.
基金Supported by the National Natural Science Foundation of China(Grants Nos. 10935013 and 11075083)the Zhejiang Provincial Natural Science Foundation of China under Grant No. Z6100077+3 种基金the FANEDD under Grant No. 200922the National Basic Research Program of China (Grant No. 2010CB832803)the NCET under Grant No. 09-0144the PCSIRT under Grant No. IRT0964
文摘We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the spherical β model）, and the luminosity distance DL from Constitution and Union2 type Ia supernova （SNe Ia） datasets. To obtain DL associated with the observed DA at the same redshift, we smooth the noise of the SNe Ia in a model-independent way, obtain the evolutionary curve of DL and, finally, test the DD relation. We find that the elliptical β model, when compared with the SNe Ia from the Constitution compilation, is only consistent with the DD relation at the 3σ confidence level （CL）, while the spherical β model is incompatible with the DD relation at the 3σ CL. For the Union2 compilation, the De Filippis and Bonamente samples are marginally compatible with the validity of the DD relation at the 1σ and 2σ CLs, respectively.
基金Supported by the Global Change Research Program China under Grant No.2015CB953904the National Natural Science Foundations of China under Grant Nos.11435005,11175092,and 11205092+1 种基金Shanghai Knowledge Service Platform for Trustworthy Internet of Things under Grant No.ZF1213K.C.Wong Magna Fund in Ningbo University
文摘The nonlocal symmetries of the Burgers equation are explicitly given by the truncated Painlevé method.The auto-B?cklund transformation and group invariant solutions are obtained via the localization procedure for the nonlocal residual symmetries. Furthermore, the interaction solutions of the solition-Kummer waves and the solition-Airy waves are obtained.
基金Supported by the Global Change Research Program of China under Grant No 2015CB953904the National Natural Science Foundation of China under Grant No 11435005+3 种基金the Shanghai Knowledge Service Platform for Trustworthy Internet of Things under Grant No ZF1213the K.C.Wong Magna Fund at Ningbo Universitythe UTRGV President's Endowed Professorshipthe Seed Grant of the UTRGV College of Science
文摘We study the Alice-Bob peakon system generated from an integrable peakon system using the strategy of the so- called Alice-Bob non-local KdV approach [Scientific Reports 7 （2017） 869]. Nonlocal integrable peakon equations are obtained and shown to have peakon solutions.
基金supported by the Ministry of Science and Technology National Basic Science Program (973) (Grant No. 2012CB821804)the National Natural Science Foundation of China (Grant Nos. 10935013,11075083,11175093,11222545 and 11375092)+4 种基金Zhejiang Provincial Natural Science Foundation of China (Grant Nos. Z6100077 and R6110518)the FANEDD (Grant No. 200922)the Hunan Provincial Natural Science Foundation of China (Grant No. 11JJ7001)the SRFDP (Grant No. 20124306110001)partially supported by China Postdoc (Grant No. 2013M530541)
文摘There is an apparent tension between cosmological parameters obtained from Planck cosmic microwave background radiation observations and that derived from the observed magnitude-redshift relation for the type Ia supernova （SNe Ia）. Here, we show that the tension can be alleviated, if we first calibrate, with the help of the distance-duality relation, the light-curve fitting parameters in the distance estimation in SNe Ia observations with the angular diameter distance data of the galaxy clusters and then re-estimate the distances for the SNe Ia with the corrected fitting parameters. This was used to explore their cosmological implications in the context of the spatially fiat cosmology. We find a higher value for the matter density parameter, Ωm, as compared to that from the original SNLS3, which is in agreement with Planck observations at 68.3% confidence. Therefore, the tension between Planck measurements and SNe Ia observations regarding Ωm can be effectively alleviated without invoking new physics or resorting to extensions for the standard concordance model. Moreover, with the absolute magnitude of a fiducial SNe Ia, M, determined first, we obtained a constraint on the Hubble constant with SNLS3 alone, which is also consistent with Planck.
基金Supported by National Natural Science Foundation of China under Grant No.11435005Ningbo Natural Science Foundation under Grant No.2015A610159+1 种基金Granted by the Opening Project of Zhejiang Provincial Top Key Discipline of Physics Sciences in Ningbo University under Grant No.xkzwl1502Sponsored by K.C.Wong Magna Fund in Ningbo University
文摘A special integrable nonlocal nonlinear Schroodinger equation, NNLS, or namely Alice-Bob NLS（ABNLS）equation is investigated. By means of the general N-th Darboux transformation, one can get various interesting solutions to display different types of structures especially for solitons. By using the Darboux transformation, its soliton solutions are obtained. Finally, by adjusting the values of free parameters, different kinds of solutions such as kinks, complexitons and rogue-wave solutions are explicitly exhibited. It is found that these solutions are quite different from the ones of the classical NLS equation.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11775146,11435005,and 11472177Shanghai Knowledge Service Platform for Trustworthy Internet of Things under Grant No.ZF1213K.C.Wong Magna Fund in Ningbo University
文摘The symmetry of the fermionic field is obtained by means of the Lax pair of the mKdV equation. A new super mKdV equation is constructed by virtue of the symmetry of the fermionic form. The super mKdV system is changed to a system of coupled bosonic equations with the bosonization approach. The bosonized SmKdV(BSmKdV)equation admits Painlevé property by the standard singularity analysis. The traveling wave solutions of the BSmKdV system are presented by the mapping and deformation method. We also provide other ideas to construct new super integrable systems.
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.
基金Acknowledgements We thank Prof. Shuang-Nan Zhang and Prof. Xiao-Feng Wang for their useful discussions. This work was supported by the National Natural Science Foundation of China under Grants Nos. 11175093, 11222545, 11435006, and 11375092, the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No. 20124306110001, and the K. C. Wong Magna Fund of Ningbo University.
文摘By using type Ia supernovae （SNIa） to provide the luminosity distance （LD） directly, which depends on the value of the Hubble constant H0 = 100h km·s^-1· Mpc^-1, and the angular diameter distance from galaxy clusters or baryon acoustic oscillations （BAOs） to give the derived LD according to the distance duality relation, we propose a model-independent method to determine h from the fact that different observations should give the same LD at a given redshift. Combining the Sloan Digital Sky Survey II （SDSS-II） SNIa from the MLCS2k2 light curve fit and galaxy cluster data, we find that at the 1σ confidence level （CL）, h = 0.5867±0.0303 for the sample of the elliptical β model for galaxy clusters, and h = 0.6199± 0.0293 for that of the spherical β model. The former is smaller than the values from other observations, whereas the latter is consistent with the Planck result at the 2σ CL and agrees very well with the value reconstructed directly from the H（z） data. With the SDSS-II SNIa and BAO measurements, a tighter constraint, h = 0.6683 ± 0.0221, is obtained. For comparison, we also consider the Union 2.1 SNIa from the SALT2 light curve fitting. The results from the Union 2.1 SNIa are slightly larger than those from the SDSS-II SNIa, and the Union 2.1 SNIa ＋ BAOs give the tightest value. We find that the values from SNIa ＋ BAOs are quite consistent with those from the Planck and the BAOs, as well as the local measurement from Cepheids and very-low-redshift SNIa.
