Fermion decoration construction of symmetry-protected trivial order for fermion systems with any symmetry and in any dimension

© 2019 American Physical Society. We use higher-dimensional bosonization and fermion decoration to construct exactly soluble interacting fermion models to realize fermionic symmetry-protected trivial (SPT) orders (which are also known as symmetry-protected topological orders) in any dimensions and for generic fermion symmetries Gf, which can be a nontrivial Z2f extension Z2Gb (where Z2f is the fermion-number-parity symmetry and Gb is the bosonic symmetry). This generalizes the previous results from group supercohomology of Gu and Wen (arXiv:1201.2648), where Gf is assumed to be Z2f×Gb. We find that the (d+1)-dimensional [(d+1)D] fermionic SPT phases with bosonic symmetry Gb and from fermion decoration construction can be described in a compact way using higher group homomorphism: BGb→φB(Z2,2;Z2,d). In fact, the fermion symmetry is more precisely described by the structure Z2f Gb SO∞ (or Z2f Gb O∞ with time-reversal symmetry). In this case the (d+1)D fermionic SPT phases are better described by B(Z2f Gb SO∞)→φB(SO∞,1;Z2,d) [or B(Z2f Gb O∞)→φB(O∞,1;Z2,d)]

Topological nonlinear σ -model, higher gauge theory, and a systematic construction of 3 + 1 D topological orders for boson systems

© 2019 American Physical Society. A discrete nonlinear σ-model is obtained by triangulate both the space-time Md+1 and the target space K. If the path integral is given by the sum of all the simplicial homomorphisms φ:Md+1→K (i.e., maps without any topological defects), with an partition function that is independent of space-time triangulation, then the corresponding nonlinear σ-model will be called topological nonlinear σ-model which is exactly soluble. These exactly soluble models suggest that phase transitions induced by fluctuations with no topological defects usually produce a topologically ordered state and are topological phase transitions. In contrast, phase transitions induced by fluctuations with all topological defects give rise to trivial product states and are not topological phase transitions. Under the classification conjecture of Lan-Kong-Wen [Phys. Rev. X 8, 021074 (2018)2160-330810.1103/PhysRevX.8.021074], it is shown that, if K is a space with only nontrivial first homotopy group G, which is finite, then these topological nonlinear σ-models can already realize all 3+1D bosonic topological orders without emergent fermions, which are described by Dijkgraaf-Witten theory with gauge group π1(K)=G. Under the similar conjecture, we show that the 3+1D bosonic topological orders with emergent fermions can be realized by topological nonlinear σ-models with π1(K)= finite groups, π2(K)=Z2, and πn>2(K)=0. A subset of these topological nonlinear σ-models corresponds to 2-gauge theories, which realize and may classify bosonic topological orders with emergent fermions that have no emergent Majorana zero modes at triple string intersections

Adverse childhood experiences and depressive symptoms among lesbian and bisexual women in China

Abstract Background Despite the relationship between Adverse childhood experiences (ACEs) and depressive symptoms, which has been well researched in general populations, little is known about homosexual and bisexual populations, especially lesbian and bisexual women in China. This study aims to investigate the prevalence of ACEs and depressive symptoms and to analyze the relationship between them among lesbian and bisexual women in China. Methods The eligible participants were aged 16 years or older who report their sexual orientation as homosexual or bisexual. The data was collected through anonymous questionnaires with the help of Lespark in Beijing from July 18 to December 29, 2018, and all participants had informed consent to this study. Univariate analysis and multiple linear regression analyses were performed to explore the relationship between ACEs and depressive symptoms among lesbian and bisexual women. All statistical analyses were conducted by the software of SPSS 22.0. Results Among 301 lesbian and bisexual women, 81.4% were lesbian, 18.4% were bisexual women, and the majority were 21–30 years. As for ACEs, 51.5% reported at least one ACE, in which emotional neglect (22.6%) and emotional abuse (22.3%) were common ACEs. As for depressive symptoms of lesbian and bisexual women, the detection rate was 56.1%. The multiple linear regression analyses showed that abuse (β = 2.95, 95%CI:1.07–4.83) and neglect (β = 3.21, 95%CI:1.09–5.31) were positively associated with depressive symptoms and lesbian and bisexual women with three (β = 4.11, 95%CI: 0.99–7.22) or more (β = 6.02, 95%CI: 3.23–8.78) ACEs suffered from more depressive symptoms than others. Conclusion Adverse childhood experiences (ACEs) and depressive symptoms were at high prevalence among lesbian and bisexual women in China. ACEs were associated with depressive symptoms, especially childhood abuse and neglect experiences that have a significant effect on lesbian and bisexual women mental health

Psychosocial health and suicidal ideation among people living with HIV/AIDS: A cross-sectional study in Nanjing, China

<div><p>Background</p><p>Suicide is a serious cause of mortality worldwide and is considered as a psychiatric emergency. People living with HIV/AIDS (PLWHA) have higher rates of suicidal behavior than the general population. This study assessed the prevalence and verified the syndemic effect of psychosocial health conditions on suicidal ideation among PLWHA in China.</p><p>Methods</p><p>An institutional-based cross-sectional study was conducted from July to August 2016 in Nanjing, China, using a self-report questionnaire. Sociodemographic characteristics, infection status, psychosocial variables and suicide ideation reports of participants were collected. Logistic regressions were used to identify potential factors associated with suicidal ideation and to verify the syndemic effect of psychosocial factors. Additionally, odds ratios (ORs) with 95% confidence intervals (95% CI) were computed.</p><p>Results</p><p>In total, four hundred sixty-five PLWHA participated, 31.6% (n = 147) of whom had suicidal ideation. The results from univariate analysis showed that older age, low education level, being married, having children, and psychosocial variables (high perceived stigma, depression, low self-esteem, social support and resilience) were significantly associated with increased suicidal ideation. Multiple logistic regression models revealed that depression (OR = 2.70, 95%CI = 1.62–4.51), perceived stigma (OR = 1.97, 95%CI = 1.17–3.32), and low social support (OR = 1.85, 95%CI = 1.08–3.20) and self-esteem (OR = 4.11, 95%CI = 2.06–8.16) were statistically significant. PLWHA with at least two psychosocial health problems were nearly 5 times more likely (OR = 4.72, 95% CI 3.11–7.17) to have had suicidal ideation.</p><p>Conclusions</p><p>Suicidal ideation is frequent among PLWHA in China and is consistent with prevalence estimates from abroad. Psychosocial health problems were the determining factors associated with suicidal ideation, and a syndemic effect of psychosocial health conditions was confirmed in predicting suicidal ideation. Therefore, early screening of high-risk groups for suicidal ideation and more psychosocial health care among PLWHA are needed.</p></div

Associations between the number of syndemic conditions and suicidal ideation among PLWHA.

<p>Associations between the number of syndemic conditions and suicidal ideation among PLWHA.</p

HIV/AIDS infection characteristics by suicidal ideation status.

<p>HIV/AIDS infection characteristics by suicidal ideation status.</p

Psychosocial variables by suicidal ideation status.

<p>Psychosocial variables by suicidal ideation status.</p