ITP OpenIR研究单元: 理论物理所2015年知识产出http://ir.itp.ac.cn/:80/handle/311006/207302018-07-19T23:21:15Z2018-07-19T23:21:15ZLarge number limit of multifield inflationGuo, ZKhttp://ir.itp.ac.cn/:80/handle/311006/221922018-06-10T16:07:57Z2018-01-29T03:31:06Z题名: Large number limit of multifield inflation
作者: Guo, ZK
摘要: We compute the tensor and scalar spectral index n(t), n(s), the tensor-to-scalar ratio r, and the consistency relation n(t)/r in the general monomial multifield slow-roll inflation models with potentials V similar to Sigma(i)lambda(i)vertical bar phi(i)vertical bar(Pi). The general models give a novel relation that nt, ns and n(t)/r are all proportional to the logarithm of the number of fields N-f when N-f is getting extremely large with the order of magnitude around O(10(40)) thorn. An upper bound N-f less than or similar to N*e(ZN)* is given by requiring the slow variation parameter small enough where N-* is the e-folding number and Z is a function of distributions of lambda(i) and rho(i). Besides, n(t)/r differs from the single-field result - 1/8 with substantial probability except for a few very special cases. Finally, we derive theoretical boundsr r > 2/N-* (r greater than or similar to 0.03) and for nt, which can be tested by observation in the near future.2018-01-29T03:31:06ZSurface structure of ionic liquids under an external electric fieldShi, RWang, YThttp://ir.itp.ac.cn/:80/handle/311006/221912018-01-29T03:36:26Z2018-01-29T03:31:05Z题名: Surface structure of ionic liquids under an external electric field
作者: Shi, R; Wang, YT
摘要: Surface structure and properties play an important role in many applications of ionic liquids (ILs). ILs can form unique surface structures that are very different from the bulk. In imidazolium-based ILs, for example, polar groups form ordered layer structure, while cationic alkyl chains are bundled together and point out from the surface. In many applications, ILs work under an external electric field. However, the effect of external electric field on the surface structure of ILs is still not clear. Here by using coarse-grained molecular dynamics simulation, we found that an electric field as strong as 1 V/nm is required to alter the surface structure of 1-dodecyl-3-methylimidazolium nitrate. Under a strong external electric field, layered structure disappears, and instead a sparser, more homogeneous and less orientationally ordered surface develops.2018-01-29T03:31:05ZModerate point: Balanced entropy and enthalpy contributions in soft matterHe, BJWang, YThttp://ir.itp.ac.cn/:80/handle/311006/221902018-01-29T03:40:22Z2018-01-29T03:31:04Z题名: Moderate point: Balanced entropy and enthalpy contributions in soft matter
作者: He, BJ; Wang, YT
摘要: Various soft materials share some common features, such as significant entropic effect, large fluctuations, sensitivity to thermodynamic conditions, and mesoscopic characteristic spatial and temporal scales. However, no quantitative definitions have yet been provided for soft matter, and the intrinsic mechanisms leading to their common features are unclear. In this work, from the viewpoint of statistical mechanics, we show that soft matter works in the vicinity of a specific thermodynamic state named moderate point, at which entropy and enthalpy contributions among substates along a certain order parameter are well balanced or have a minimal difference. Around the moderate point, the order parameter fluctuation, the associated response function, and the spatial correlation length maximize, which explains the large fluctuation, the sensitivity to thermodynamic conditions, and mesoscopic spatial and temporal scales of soft matter, respectively. Possible applications to switching chemical bonds or allosteric biomachines determining their best working temperatures are also briefly discussed.2018-01-29T03:31:04ZStable strange quark matter objects with running masses and coupling constantXia, CJZhou, SGhttp://ir.itp.ac.cn/:80/handle/311006/221892018-01-29T03:44:23Z2018-01-29T03:31:03Z题名: Stable strange quark matter objects with running masses and coupling constant
作者: Xia, CJ; Zhou, SG
摘要: We improve our recently proposed unified description for strange quark matter (SQM) objects, in the way that analytical expressions are derived and used to calculate the distribution of particles inside an SQM object. In the improved model, the computational time is greatly reduced without losing accuracy. The properties of SQM objects are then investigated by adopting perturbative quantum chromodynamics with running quark masses and coupling constant. Aside from the increase of masses and radii of strange stars, it is found that the perturbative interactions also make the electric field on the surface stronger and extends deeper into the core, while small SQM objects become less compact and more positively charged. These may affect the experimental searches of SQM. (C) 2017 The Author(s). Published by Elsevier B.V.2018-01-29T03:31:03ZMolecular Origin of Donor- and Acceptor-Rich Domain Formation in Bulk-Heterojunction Solar Cells with an Enhanced Charge Transport EfficiencyLong, GKShi, RZhou, YCLi, ALKan, BWu, WRJeng, USXu, TYan, TYZhang, MTYang, XSun, LTGray-Weale, AWan, XJZhang, HTLi, CXWang, YTChen, YShttp://ir.itp.ac.cn/:80/handle/311006/221882018-01-29T03:37:27Z2018-01-29T03:31:01Z题名: Molecular Origin of Donor- and Acceptor-Rich Domain Formation in Bulk-Heterojunction Solar Cells with an Enhanced Charge Transport Efficiency
作者: Long, GK; Shi, R; Zhou, YC; Li, AL; Kan, B; Wu, WR; Jeng, US; Xu, T; Yan, TY; Zhang, MT; Yang, X; Sun, LT; Gray-Weale, A; Wan, XJ; Zhang, HT; Li, CX; Wang, YT; Chen, YS
摘要: Understanding the origin of different morphologies in bulk-heterojunction solar cells can provide effective guidelines to rational control of the morphologies in the active layer. Here, we have uncovered the importance of molecular interactions on the morphologies for not only donor materials but also for fiillerene acceptors in organic solar cells through the multiscale coarse-graining molecular dynamic simulations at the real device level (similar to 83 nm x 83 nm x 83 nm). It is found that oligothiophene donors with polar end groups could not only facilitate the formation of continuous donor network but also promote the aggregation and connection of fullerenes toward efficient hole and electron transport. On the contrary, fullerenes are well dispersed at the molecule levels in the less polar oligothiophene matrix and thus contribute to the poor electron transport mobility and device performance, which is consistent with the observed differences in both morphology and charge transport properties of these two systems. These results would provide effective guidelines for the rational molecule design and morphology control to further enhance the device performance of organic solar cells.2018-01-29T03:31:01ZHunting for heavy majorana neutrinos with lepton number violating signatures at LHCGuo, CGuo, SYHan, ZLLi, BLiao, Yhttp://ir.itp.ac.cn/:80/handle/311006/221872018-01-29T03:36:17Z2018-01-29T03:31:00Z题名: Hunting for heavy majorana neutrinos with lepton number violating signatures at LHC
作者: Guo, C; Guo, SY; Han, ZL; Li, B; Liao, Y
摘要: The neutrinophilic two-Higgs-doublet model (v2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar phi(nu), (H-+/-, H, A) and singlet neutrinos N-R of TeV scale. In this paper, we perform detailed simulations for the lepton number violating (LNV) signatures at LHC arising from cascade decays of the new scalars and neutrinos with the mass order mN(R), < rn phi(nu). Under constraints from lepton flavor violating processes and direct collider searches, their decay properties are explored and lead to three types of LNV signatures: 2l(+/-)4j+ E-T, 3l(+/-)4j+E-T, and 3l(+/-)l(-/+)4j. We find that the same-sign trilepton signature 3l(+/-)4j + E-T is quite unique and is the most promising discovery channel at the high-luminosity LHC. Our analysis also yields the 95% C.L. exclusion limits in the plane of the phi(nu) and N-R masses at 13 (14) TeV LHC with an integrated luminosity of 100 (3000) fb(-1).2018-01-29T03:31:00ZEffect of the early reionization on the cosmic microwave background and cosmological parameter estimatesHuang, QGWang, Khttp://ir.itp.ac.cn/:80/handle/311006/221862018-01-29T03:38:04Z2018-01-29T03:30:59Z题名: Effect of the early reionization on the cosmic microwave background and cosmological parameter estimates
作者: Huang, QG; Wang, K
摘要: The early reionization (ERE) is supposed to be a physical process which happens after recombination, but before the instantaneous reionization caused by the first generation of stars. We investigate the effect of the ERE on the temperature and polarization power spectra of cosmic microwave background (CMB), and adopt principal components analysis (PCA) to model-independently reconstruct the ionization history during the ERE. In addition, we also discuss how the ERE affects the cosmological parameter estimates, and find that the ERE does not impose any significant influences on the tensor-to-scalar ratio r and the neutrino mass at the sensitivities of current experiments. The better CMB polarization data can be used to give a tighter constraint on the ERE and might be important for more precisely constraining cosmological parameters in the future.2018-01-29T03:30:59ZGravitational wave signals of electroweak phase transition triggered by dark matterChao, WGuo, HKShu, Jhttp://ir.itp.ac.cn/:80/handle/311006/221852018-01-29T03:41:14Z2018-01-29T03:30:57Z题名: Gravitational wave signals of electroweak phase transition triggered by dark matter
作者: Chao, W; Guo, HK; Shu, J
摘要: We study in this work a scenario that the universe undergoes a two step phase transition with the first step happened to the dark matter sector and the second step being the transition between the dark matter and the electroweak vacuums, where the barrier between the two vacuums, that is necessary for a strongly first order electroweak phase transition (EWPT) as required by the electroweak baryogenesis mechanism, arises at the tree-level. We illustrate this idea by working with the standard model (SM) augmented by a scalar singlet dark matter and an extra scalar singlet which mixes with the SM Higgs boson. We study the conditions for such pattern of phase transition to occur and especially for the strongly first order EWPT to take place, as well as its compatibility with the basic requirements of a successful dark matter, such as observed relic density and constraints of direct detections. We further explore the discovery possibility of this pattern EWPT by searching for the gravitational waves generated during this process in spaced based interferometer, by showing a representative benchmark point of the parameter space that the generated gravitational waves fall within the sensitivity of eLISA, DECIGO and BBO.2018-01-29T03:30:57ZProbing the No-Scale F-SU(5) one-parameter model via gluino searches at the LHC2Li, TJMaxin, JANanopoulos, DVhttp://ir.itp.ac.cn/:80/handle/311006/221842018-01-29T03:43:08Z2018-01-29T03:30:55Z题名: Probing the No-Scale F-SU(5) one-parameter model via gluino searches at the LHC2
作者: Li, TJ; Maxin, JA; Nanopoulos, DV
摘要: In our recent paper entitled "The return of the King: No-Scale F-SU(5)", we showed that the model space supporting the most favorable phenomenology should have been probed in 2016 at the LHC2, with an even further reach into this region of the model in 2017-18. This ideal realm of the one-parameter version of No-Scale F-SU(5) yields a 1.9-2.3 TeV gluino mass at the very same point where the light Higgs boson mass enters its rather narrow experimentally determined range of m(h)=125.09 +/- 0.24 GeV. Given the recent results reported at Moriond 2017 for 36 fb(-1) of luminosity collected in 2016 at the 13 TeV LHC2, we now update the status of the No-Scale F-SU(5) model space in light of the gluino mass exclusion limits presented by the ATLAS and CMS Collaborations. We illustrate that a resolution could be reached soon as to whether supersymmetry lives in this most critical region of the model space. (C) 2017 The Authors. Published by Elsevier B.V.2018-01-29T03:30:55ZCorrelation Effects and Hidden Spin-Orbit Entangled Electronic Order in Parent and Electron-Doped Iridates Sr2IrO4Zhou, SJiang, KChen, HWang, ZQhttp://ir.itp.ac.cn/:80/handle/311006/221832018-01-29T03:38:52Z2018-01-29T03:30:54Z题名: Correlation Effects and Hidden Spin-Orbit Entangled Electronic Order in Parent and Electron-Doped Iridates Sr2IrO4
作者: Zhou, S; Jiang, K; Chen, H; Wang, ZQ
摘要: Analogs of the high-T-c cuprates have been long sought after in transition metal oxides. Because of the strong spin-orbit coupling, the 5d perovskite iridates Sr2IrO4 exhibit a low-energy electronic structure remarkably similar to the cuprates. Whether a superconducting state exists as in the cuprates requires understanding the correlated spin-orbit entangled electronic states. Recent experiments discovered hidden order in the parent and electron-doped iridates, some with striking analogies to the cuprates, including Fermi surface pockets, Fermi arcs, and pseudogap. Here, we study the correlation and disorder effects in a five-orbital model derived from the band theory. We find that the experimental observations are consistent with a d-wave spin-orbit density wave order that breaks the symmetry of a joint twofold spin-orbital rotation followed by a lattice translation. There is a Berry phase and a plaquette spin flux due to spin procession as electrons hop between Ir atoms, akin to the intersite spin-orbit coupling in quantum spin Hall insulators. The associated staggered circulating J(eff) = 1/2 spin current can be probed by advanced techniques of spin-current detection in spintronics. This electronic order can emerge spontaneously from the intersite Coulomb interactions between the spatially extended iridium 5d orbitals, turning the metallic state into an electron-doped quasi-2D Dirac semimetal with important implications on the possible superconducting state suggested by recent experiments.2018-01-29T03:30:54Z