1,721,106 research outputs found
Two-dimensional SCFTs from wrapped branes and c-extremization
No full textWe apply c-extremization, whose proof we review in full detail, to study two-dimensional N=(0,2) superconformal field theories arising from the low-energy dynamics of D3-branes wrapped on Riemann surfaces and M5-branes wrapped on four-manifolds. We compute the exact central charges of these theories using anomalies and c-extremization. In all cases we also construct AdS3 supergravity solutions of type IIB and eleven-dimensional supergravity, which are holographic duals to the field theories at large N, and exactly reproduce the central charges computed via c-extremization
Remarks on the N=1 SU(M+p) x SU(p) quiver gauge theory with flavor
No full textWe study supersymmetric vacua of the N=1 cascading SU(M+p)×SU(p) gauge theory with flavor—the theory on p D3-branes and M wrapped D5-branes at the tip of the conifold, and Nf flavor D7-branes wrapping a holomorphic four-cycle inside the conifold. The Coulomb branch of the moduli space is inherited from the pure gauge theory without flavor and was thoroughly studied in the past. Besides, there is a Higgs branch where some D3- and/or D5-branes dissolve in the D7-branes forming the worldvolume gauge instantons. We study the Higgs branch both from the field theory and the bulk point of view. On the classical level the moduli space is closely related to the one of the N=2 C2/Z2 orbifold theory, in particular, certain vacua of the N=1 theory are related to noncommutative instantons on the resolved C2/Z2. On the quantum level the Higgs branch acquires corrections due to renormalization of the Kähler potential and nonperturbative effects in field theory. In the bulk this is encoded in the classical D7-brane geometry. We compute the vacuum expectation value (VEV)s of the protected operators and the field theory RG flow and find an agreement with the parallel computations in the bulk
Exact Two-Dimensional Superconformal R Symmetry and c Extremization
No full textWe uncover a general principle dubbed c extremization, which determines the exact R symmetry of a two-dimensional unitary superconformal field theory with N=(0,2) supersymmetry. To illustrate its utility, we study superconformal theories obtained by twisted compactifications of four-dimensional N=4 super–Yang-Mills theory on Riemann surfaces and construct their gravity duals
Superconformal index of low-rank gauge theories via the Bethe Ansatz
Full text linkWe study the Bethe Ansatz formula for the superconformal index, in the case of 4d N = 4 super-Yang-Mills with gauge group SU(N). We observe that not all solutions to the Bethe Ansatz Equations (BAEs) contribute to the index, and thus formulate “reduced BAEs” such that all and only their solutions contribute. We then propose, sharpening a conjecture of Arabi Ardehali et al., that there is a one-to-one correspondence between branches of solutions to the reduced BAEs and vacua of the 4d N = 1* theory. We test the proposal in the case of SU(2) and SU(3). In the case of SU(3), we confirm that there is a continuous family of solutions, whose contribution to the index is non-vanishing
Noise exposure in neonatal intensive care units
No full textThis study evaluates the exposure of newborn babies in neonatal intensive care units (NICU) to noise which can cause hearing lesions directly (acoustic trauma) as well as indirectly (hypoxia). Moreover, noise can have an aggravating effect when combined with other potentially harmful factors in the NICU, such as ototoxic medication or stress due to other external stimuli, such as excessively bright light, lack of a day/night rhythm or pain. Sound pressure levels were measured in the NICU and inside the cribs in various experimental conditions, classified under 3 different types of sound events: constant background noise, variations in background noise and impulsive events. The main sources of noise detected were crib noise generated by ventilation and temperature control systems, ambient noise in the room, noise caused by the staff in the NICU, noise generated by crib alarm systems and NICU apparatus and noise caused by activity on the crib cover or on its plexiglas top. Findings revealed that the influence of ambient noise is fairly irrelevant. Background noise and its variations concerned with activities in the department never exceeded the limits considered potentially harmful to adults (DRC), whereas the impulsive noise generated by staff on the cribs or on the plexiglas tops was considerable and potentially harmful. These findings demonstrate that it is feasible and relatively easy to control noise in the NICU and significantly reduce the impulsive noise component by training staff to be more careful and avoid any unnecessary jolting and rough handling on and near the cribs
Attention and reaction to distress in infancy: A longitudinal study
No full textThe primary aim of this study was to verify whether early individual differences in look duration are related to general mechanisms of the infant nervous system that draw together attention and emotion. Thirty-one infants were observed at 3, 5, and 11 months of age. Facial expressions of pain and distress were observed by means of C. Izard's (1979) Maximally Discriminative Facial Movement Coding System 90 s after routine pediatric vaccinations. Several measures of visual attention were taken experimentally in a separate testing session. Significant correlations between measures of attention and duration of facial expressions of pain and distress were found at each age level. Infants who showed pain or distress for a shorter time period also paid attention for a shorter time period and vice versa. The main conclusion is that individual differences combining control of both pain and attention can be identified from early infancy
Conformality Loss, Walking, and 4D Complex Conformal Field Theories at Weak Coupling
Full text linkFour-dimensional gauge theories with matter can have regions in parameter space, often dubbed conformal windows, where they flow in the infrared to nontrivial conformal field theories. It has been conjectured that conformality can be lost because of merging of two nearby fixed points that move into the complex plane, and that a walking dynamics governed by scaling dimensions of operators defined at such complex fixed points can occur. We find controlled, parametrically weakly coupled, and ultraviolet-complete 4D gauge theories that explicitly realize this scenario. We show how the walking dynamics is controlled by the coupling of a double-trace operator that crosses marginality. The walking regime ends when the renormalization group flow of this coupling leads to a (weak) first-order phase transition with Coleman-Weinberg symmetry breaking. A light dilatonlike scalar particle appears in the spectrum, but it is not parametrically lighter than the other excitations
4d index to 3d index and 2d topological quantum field theory
No full textWe compute the 4d superconformal index for N=1, 2 gauge theories on S1×L(p,1), where L(p,1) is a lens space. We find that the 4d N=1, 2 index on S1×L(p,1) reduces to a 3d N=2, 4 index on S1×S2 in the large p limit, and to a 3d partition function on a squashed L(p,1) when the size of the temporal S1 shrinks to zero. As an application of our index, we study 4d N=2 superconformal field theories arising from the 6d N=(2,0) A1 theory on a punctured Riemann surface Σ, and conjecture the existence of a 2d topological quantum field theory on Σ whose correlation function coincides with the 4d N=2 index on S1×L(p,1)
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