Explaining Movements in Completed Fertility Across Cohorts

A life cycle model of fertility based on the quantity-quality model of fertility successfully explains changes in completed fertility in a period in which completed fertility first fell and then rose. This model furthermore accurately predicts the timing and level of the subsequent peak in completed fertility. Regressions based on Easterlin's relative economic status theory of fertility are less successful in predicting fertility over a fifteen year period than regressions based on the quantity-quality model. Upon investigation, much of the increase in completed fertility associated with the baby boom appears to be primarily attributable to sporadic wage growth.

Ambiguity in the Determination of the Free Energy for a Model of the Circle Map

We consider a simple model to describe the widths of the mode locked intervals for the critical circle map. Using two different partitions of the rational numbers, based on Farey series and Farey tree levels respectively, we calculate the free energy analytically at selected points for each partition. It is found that the result of the calculation depends on the method of partition. An implication of this is that the generalized dimensions $D_q$ are different for each partition except when $q=0$, i.e. only the Hausdorff dimension is the same in each case.Comment: 14 page

Measurement of the entanglement spectrum of a symmetry-protected topological state using the IBM quantum computer

Entanglement properties are routinely used to characterize phases of quantum matter in theoretical computations. For example the spectrum of the reduced density matrix, or so-called "entanglement spectrum", has become a widely used diagnostic for universal topological properties of quantum phases. However, while being convenient to calculate theoretically, it is notoriously hard to measure in experiments. Here we use the IBM quantum computer to make the first ever measurement of the entanglement spectrum of a symmetry-protected topological state. We are able to distinguish its entanglement spectrum from those we measure for trivial and long-range ordered states.Comment: 8 pages, 4 figure

Prove It!

A dialogue between a mathematics professor, Frank, and his daughter, Sarah, a mathematical savant with a powerful mathematical intuition. Sarah\u27s intuition allows her to stumble into some famous theorems from number theory, but her lack of academic mathematical background makes it difficult for her to understand Frank\u27s insistence on the value of proof and formality

Formation of Self-Aligned Shallow Junction MOSFET Source/Drains by Proximity Rapid Thermal Diffusion

The creation of short-channel length MOSFET\u27s requires shallow junctions and thin gate dielectrics to maintain long channel behavior. The Focus of this paper is the creation of shallow source/drain junctions by Proximity Diffusion with Rpid Thermal Processing (RTP_. PMOS devices were fabricated using Borofilm 100 Spin on Dopant with temperatures pf 950° and 1000° for 10 and 20 seconds ramped at 30 degrees per second. The source and drain regions are defined by the patterned polysilicon gate, which is also doped during this process. A 100 A gate oxide is used, incorporating nitrogen to reduce boron diffusion through the gate. The devices were tested and working transistors were found down to 0.6 micron mask defined gate lengths. The threshold voltage for these devices was found to be -3.1 Volts. Samples sent out for analysis by Secondary Ion Mass Spectrometry (SIMS) to profile the boron diffusion. The approximate junction depth was found to be between 30 and 40 A for the sample ran at 950° C for 10 seconds

Electron tunnel sensor technology

Researchers designed and constructed a novel electron tunnel sensor which takes advantage of the mechanical properties of micro-machined silicon. For the first time, electrostatic forces are used to control the tunnel electrode separation, thereby avoiding the thermal drift and noise problems associated with piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded cantilever spring and a tip. The application of this sensor to the development of a sensitive accelerometer is described

A synopsis of test results and knowledge gained from the Phase-0 CSI evolutionary model

The Phase-0 CSI Evolutionary Model (CEM) is a testbed for the study of space platform global line-of-sight (LOS) pointing. Now that the tests have been completed, a summary of hardware and closed-loop test experiences is necessary to insure a timely dissemination of the knowledge gained. The testbed is described and modeling experiences are presented followed by a summary of the research performed by various investigators. Some early lessons on implementing the closed-loop controllers are described with particular emphasis on real-time computing requirements. A summary of closed-loop studies and a synopsis of test results are presented. Plans for evolving the CEM from phase 0 to phases 1 and 2 are also described. Subsequently, a summary of knowledge gained from the design and testing of the Phase-0 CEM is made

Octa­rubidium di-μ-sulfato-κ4 O:O′-bis­[cis-dioxido-cis-disulfatotungstate(VI)]

The title compound, Rb8[W2O4(SO4)6], was precipitated from a melt of tungsten(VI) oxide and rubidium sulfate in rubidium disulfate. The unit cell contains two discrete [{WVIO2(SO4)2}2(μ-SO4)2]8− units connected by Rb–O coord­ination. The W atom is octahedrally surrounded by two oxide ligands, two terminal sulfate ligands and two bridging sulfate groups. One Rb atom is coordinated by eight O atoms, whereas the three other Rb atoms are coordinated by nine O atoms from sulfate and oxide groups, leading to distorted [RbOx] polyhedra