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We study competition between s-wave order and d-wave order through two holographic superconductor models. We find that once the coexisting phase appears, it is always thermodynamically favored, and that the coexistence phase is narrow and one condensate tends to kill the other. The phase diagram is constructed for each model in terms of temperature and the ratio of charges of two orders. We further compare the behaviors of some thermodynamic quantities, and discuss the different aspects and identical ones between two models., Comment: 3 figures added, accepted by JHEP

We study in detail the phase structure of a holographic p-wave superconductor model in a five dimensional Einstein-Maxwell-complex vector field theory with a negative cosmological constant. To construct complete phase diagrams of the model, we consider both the soliton and black hole backgrounds. In both two cases, there exist second order, first order and zeroth order phase transitions, and the so-called "retrograde condensation" also happens. In particular, in the soliton case with the mass of the vector field being beyond a certain critical value, we find a series of phase transitions happen such as "insulator/superconductor/insulator/superconductor", as the chemical potential continuously increases. We construct complete phase diagrams in terms of temperature and chemical potential and find some new phase boundaries., 47 pages, 25 figures, added references, modified some figures

We study a holographic p-wave superconductor model in a four dimensional Einstein-Maxwell-complex vector field theory with a negative cosmological constant. The complex vector field is charged under the Maxwell field. We solve the full coupled equations of motion of the system and find black hole solutions with the vector hair. The vector hairy black hole solutions are dual to a thermal state with the U(1) symmetry as well as the spatial rotational symmetry breaking spontaneously. Depending on two parameters, the mass and charge of the vector field, we find a rich phase structure: zeroth order, first order and second order phase transitions can happen in this model. We also find "retrograde condensation" in which the hairy black hole solution exists only for the temperatures above a critical value with the free energy much larger than the black hole without hair. We construct the phase diagram for this system in terms of the temperature and charge of the vector field., v3: 26 pages, 15 figures, references added, extra arguments added, to appear in JHEP

We continue to study the holographic p-wave superconductor model in the Einstein-Maxwell-complex vector field theory with a non-minimal coupling between the complex vector field and the Maxwell field. In this paper we work in the AdS soliton background which describes a conformal field theory in the confined phase and focus on the probe approximation. We find that an applied magnetic field can lead to the condensate of the vector field and the AdS soliton instability. As a result, a vortex lattice structure forms in the spatial directions perpendicular to the applied magnetic field. As a comparison, we also discuss the vector condensate in the Einstein-SU(2) Yang-Mills theory and find that in the setup of the present paper, the Einstein-Maxwell-complex vector field model is a generalization of the SU(2) model in the sense that the vector field has a general mass and gyromagnetic ratio., v2: minor changes, to appear in JHEP. arXiv admin note: text overlap with arXiv:1309.2098

We study a holographic model with vector condensate by coupling the anti-de Sitter gravity to an Abelian gauge field and a charged vector field in $(3+1)$ dimensional spacetime. In this model there exists a non-minimal coupling of the vector filed to the gauge field. We find that there is a critical temperature below which the charged vector condenses via a second order phase transition. The DC conductivity becomes infinite and the AC conductivity develops a gap in the condensed phase. We study the effect of a background magnetic field on the system. It is found that the background magnetic field can induce the condensate of the vector field even in the case without chemical potential/charge density. In the case with non-vanishing charge density, the transition temperature raises with the applied magnetic field, and the condensate of the charged vector operator forms a vortex lattice structure in the spatial directions perpendicular to the magnetic field., v3: minor changes, references added, to appear in JHEP

Virus reservoirs can persist in human immunodeficiency virus type 1 (HIV-1)-infected subjects despite effective plasma virus suppression. To compare viral dynamics in the absence and presence of antiretroviral therapy, blood mononuclear cells from 19 subjects with high plasma RNA levels and 18 subjects following prolonged virus suppression were examined, by use of in situ hybridization, to detect virus RNA expression before and after in vitro T cell activation. This approach reveals circulating lymphocytes expressing HIV-1 RNA before activation and an increase in cells with detectable HIV-1 RNA transcription after in vitro activation. The frequencies of these 2 cell populations are strongly correlated with plasma virus load and appear to be stable once a new steady state is established during therapy. The frequency of viral RNA-positive cells is equivalent to the frequency of cells that produce infectious virus. Thus, in HIV-1-infected subjects there are distinct virus reservoirs comprising both latent and replication-active cells.

We study the Wilson line response in the holographic superconducting phase transitions in Gauss-Bonnet gravity. In the black brane background case, the Little-Parks periodicity is independent of the Gauss-Bonnet parameter, while in the AdS soliton case, there is no evidence for the Little-Parks periodicity. We further study the impact of the Gauss-Bonnet term on the holographic phase transitions quantitatively. The results show that such quantum corrections can effectively affect the occurrence of the phase transitions and the response to the Wilson line., 19 pages, 6 figures, 2 tables, references added

We continue our study of entanglement entropy in the holographic superconducting phase transitions. In this paper we consider the holographic p-wave superconductor/insulator model, where as the back reaction increases, the transition is changed from second order to first order. We find that unlike the s-wave case, there is no additional first order transition in the superconducting phase. We calculate the entanglement entropy for two strip geometries. One is parallel to the super current, and the other is orthogonal to the super current. In both cases, we find that the entanglement entropy monotonically increases with respect to the chemical potential., Comment: v2: title changed, discussions improved, references added, accepted by JHEP

In a recent paper, arXiv:1309.4877, a holographic p-wave model has been proposed in an Einstein-Maxwell-complex vector field theory with a negative cosmological constant. The model exhibits rich phase structure depending on the mass and the charge of the vector field. We investigate the behavior of the entanglement entropy of dual field theory in this model. When the above two model parameters change, we observe the second order, first order and zeroth order phase transitions from the behavior of the entanglement entropy at some intermediate temperatures. These imply that the entanglement entropy can indicate not only the occurrence of the phase transition, but also the order of the phase transition. The entanglement entropy is indeed a good probe to phase transition. Furthermore, the "retrograde condensation" which is a sub-dominated phase is also reflected on the entanglement entropy., Comment: figures added; accepted by Nuclear Physics b

We study the behaviors of entanglement entropy and vacuum expectation value of Wilson loop in the St\"{u}ckelberg holographic insulator/superconductor model. This model has rich phase structures depending on model parameters. Both the entanglement entropy for a strip geometry and the heavy quark potential from the Wilson loop show that there exists a "confinement/deconfinement" phase transition. In addition, we find that the non-monotonic behavior of the entanglement entropy with respect to chemical potential is universal in this model. The pseudo potential from the spatial Wilson loop also has a similar non-monotonic behavior. It turns out that the entanglement entropy and Wilson loop are good probes to study the properties of the holographic superconductor phase transition., Comment: 23 pages,12 figures. v2: typos corrected, accepted in JHEP

In this paper we study the non-Gaussian features of the primordial fluctuations in loop quantum cosmology with the inverse volume corrections. The detailed analysis is performed in the single field slow-roll inflationary models. However, our results reflect the universal characteristics of bispectrum in loop quantum cosmology. The main corrections to the scalar bispectrum come from two aspects: one is the modifications to the standard Bunch-Davies vacuum, the other is the corrections to the background dependent variables, such as slow-roll parameters. Our calculations show that the loop quantum corrections make $f_{{\rm NL}}$ of the inflationary models increase 0.1%. Moreover, we find that two new shapes arise, namely $\mathcal F_{1}$ and $\mathcal F_{2}$. The former gives a unique loop quantum feature which is less correlated with the local, equilateral and single types, while the latter is highly correlated with the local one., Comment: matched to the published version. 30 pages, 4 figures

The effort toward making quantum mechanics and general relativity compatible (quantum gravity) has lasted more than a century. The string theory and loop quantum gravity both stand out as strong candidates and currently they both make popular research subjects in quantum gravity. As we known, Loop quantum gravity (LQG)(Ashtekar & Lewandowski, 2004; Rovelli, 1998; 2004; Thiemann, 2007) is a background independent and non-perturbative canonical quantum gravity theory. LQG has made many breakthroughs in recent years: the establishment of the quantum Einstein equations Ashtekar & Tate (1994); Ashtekar et al. (1995a); Corichi & Zapata (1997); Lewandowshi & Thiemann (1999); Rovelli & Smolin (1994); Thiemann (1996; 1998a;b;c; 2001), the proof that the Riemannian operators have discrete eigenvalues Ashtekar et al. (1995b); Lewandowski (1997); Loll (1995a;b; 1997a;b); Rovilli & Smolin (1995); Thiemann (1998d;e),results concerning the entropy of the black hole horizon and cosmological horizon entropy with statistical mechanics Ashtekar et al. (1998; 1999; 2000; 2001; 2002; 2003a;b); Berreira et al. (1996); Rovelli (1996a;b); Smolin (1995), and so on. As an application of loop quantum gravity to cosmology, loop quantum cosmology (LQC) Bojowald (2005a; 2008); Date (2002) also presents itself as a possible path toward answers to the cosmological and astrophysical riddles. As a symmetry reduced model of LQG, LQC inherits the quantum schemes originated from LQG that dealt with the isotropic and homogeneous universe firstly and then extended to the inhomogeneous and anisotropic model Bojowald (2002a). It plays an important role in connecting the LQG theory and the measureable world. On one hand, it is used to test the full theory, which, in its own form, is extremely complex and difficult to directly apply.On the other hand, making connections to the real world sheds light on further improvement of the LQG theory. These reasons make LQC a promising and enlightening subject to study. In LQC, the collapsing and expanding phases are connected by the cyclic or oscillatorymodels Lidsey et al. (2004), and the universe is automatically born with a small scale factor at the fixed point near the Planck phase Bojowald (2005); Mulryne et al. (2005a). Unlike in the emergent universe model, this fixed point here is stable and allows the universe to start in an initial phase of oscillation. Then an inflationary phase is entered, which is the relevant regime for structure formation. In LQC, there aremany different inflationary scenarios Artymowski et al. (2009); Bojowald et al. (2004); Mulryne et al. (2005b); Zhang & Ling (2007), among which the one without inflation is the most attractive, mainly because it can explain the inflationary phase directly from LQG. But, unfortunately, it is difficult to study the structure formation. 16

The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the loop gravity theory and one version of this conjecture. Recently, S. He and H. Zhang proposed a version for the dynamical horizon of the universe, which validates the entropy bound conjecture for the cosmology filled with perfect fluid in the classical scenario when the universe is far away from the big bang singularity. However, their conjecture breaks down near big bang region. We examine this conjecture in the context of the loop quantum cosmology. With the example of photon gas, this conjecture is protected by the quantum geometry effects as expected., Comment: 4 pages, 2 figures, revised version

A well-motivated extension of higher order holonomy corrections in loop quantum cosmology (LQC) for the k=0 Friedmann-Robertson-Walker model is investigated at the level of heuristic effective dynamics. It reveals that the quantum bounce is generic, regardless of the order of corrections, and the matter density remains finite, bounded from above by an upper bound in the regime of the Planckian density, even if all orders of corrections are included. This observation provides further evidence that the quantum bounce is essentially a consequence of the loopy nature (i.e. intrinsic discreteness) of LQC and LQC is fundamentally different from the Wheeler-DeWitt theory; it also encourages one to construct the quantum theory of LQC with the higher order holonomy corrections, which might be understood as related to the higher j representations in the Hamiltonian operator of loop quantum gravity.

Wormhole and time machine are very interesting objects in general relativity. However, they need exotic matters which are impossible in classical level to support them. But if we introduce the quantum effects of gravity into the stress-energy tensor, these peculiar objects can be constructed self-consistently. Fortunately, loop quantum cosmology (LQC) has the potential to serve as a bridge connecting the classical theory and quantum gravity. Therefore it provides a simple way for the study of quantum effect in the semiclassical case. As is well known, loop quantum cosmology is very successful to deal with the behavior of early universe. In the early stage, if taken the quantum effect into consideration, inflation is natural because of the violation of every kind of local energy conditions. Similar to the inflationary universe, the violation of the averaged null energy condition is the necessary condition for the traversable wormholes. In this paper, we investigate the averaged null energy condition in LQC in the framework of effective Hamiltonian, and find out that LQC do violate the averaged null energy condition in the massless scalar field coupled model., 5 pages

Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but are actually also found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid., Comment: 4 pages

Loop quantum cosmology (LQC) predicts a nonsingular evolution of the universe through a bounce in the high energy region. But LQC has an ambiguity about the quantization scheme. Recently, the authors in [Phys. Rev. D 77, 124008 (2008)] proposed a new quantization scheme. Similar to others, this new quantization scheme also replaces the big bang singularity with the quantum bounce. More interestingly, it introduces a quantum singularity, which is traversable. We investigate this novel dynamics quantitatively with a tachyon scalar field, which gives us a concrete example. Our result shows that our universe can evolve through the quantum singularity regularly, which is different from the classical big bang singularity. So this singularity is only a week singularity., 7 pages, 3 figures. Accepted for publication in Physical Review D

To study the possible mechanism of intrauterine infection of hepatitis B virus (HBV).HBV DNA was examined in amniotic fluid, and vaginal secretion of 59 HBsAg positive mothers and in cord blood of their neonates by PCR. Ten negative hepatitis B virus marker (HBVM) mothers and their neonates were served as control. HBsAg and HBcAg in placenta were examined by avidin biotin complex (ABC) method.The detection rate of HBV DNA in amniotic fluid, vaginal secretion and neonatal cord blood of the study group were 47.5% (28/59), 52.5% (31/59) and 45.8% (27/59) respectively. HBsAg and HBcAg in placenta was distributed in the following descending order: maternal decidual cells, trophoblastic cells, villous mesenchymal cells and villous capillary endothelial cells. But the distribution was in reverse order in 4 placentas. HBsAg and HBcAg were detected in amniotic epithelial cells in 32 mothers.The main route of HBV transmission from mother to fetus is transplacental, from maternal side of placenta to fetal side. However, HBV intrauterine infection may take place through other routes.

Exposure to ethanol in utero compromises the offspring's developing immune and endocrine systems. Persistent functional changes, particularly in T-cell-dependent aspects of immunity and in hypothalamic-pituitary-adrenal activity, are commonly seen. The present study examined the degree to which fetal alcohol exposure (FAE) during development suppressed the lymphocyte proliferative response to Concanavalin-A (Con A). We also examined the effect of maternal adrenalectomy on the expression of glucocorticoid-regulated genes and the response to Con A in FAE offspring. Con A-stimulated lymphocyte proliferation was stably suppressed (between 28-46%) in FAE males compared to isocalorically pair-fed offspring at 7, 21, 40, and 60 days of age. In contrast, lymphocyte proliferation in the immature or peripubertal FAE female was totally unaffected. In 60-day- old male rats, maternal adrenalectomy reversed the FAE-induced suppression of Con A-stimulated proliferation, but had no effect on lymphocyte proliferation. FAE increased anterior pituitary POMC (the precursor of ACTH) mRNA levels dramatically in males, and this increase was also reversed by maternal adrenalectomy. In both sexes, anterior pituitary glucocorticoid receptor mRNA levels were unaffected by prenatal alcohol exposure alone, but were significantly decreased in male and increased in female offspring of adrenalectomized dams ingesting alcohol. Furthermore, in male, but not female, offspring, hypothalamic levels of glucocorticoid receptor and CRF mRNA were increased significantly by FAE alone or in combination with maternal adrenalectomy. In female, but not male, offspring, maternal adrenalectomy with concomitant alcohol exposure increased anterior pituitary POMC mRNA levels compared to that in sham/pair-fed offspring. In summary, FAE induced a gender-specific impairment of Con A-stimulated lymphocyte proliferation. This deficit is present both before and after puberty, demonstrating its stability into adulthood. Furthermore, in males, maternal adrenalectomy reversed these FAE-induced deficits in T-cell function as well as the effect of FAE on anterior pituitary POMC expression. This supports the hypothesis that maternal adrenal hormones participate in the immunosuppressive "imprinting" of the FAE fetus and are, therefore, causally implicated in the sexually dimorphic T-cell dysfunction found in FAE offspring.