Synthetic clock transitions via continuous dynamical decoupling

Decoherence of quantum systems due to uncontrolled fluctuations of the environment presents fundamental obstacles in quantum science. `Clock' transitions which are insensitive to such fluctuations are used to improve coherence, however, they are not present in all systems or for arbitrary system parameters. Here, we create a trio of synthetic clock transitions using continuous dynamical decoupling in a spin-1 Bose-Einstein condensate in which we observe a reduction of sensitivity to magnetic field noise of up to four orders of magnitude; this work complements the parallel work by Anderson et al. (submitted, 2017). In addition, using a concatenated scheme, we demonstrate suppression of sensitivity to fluctuations in our control fields. These field-insensitive states represent an ideal foundation for the next generation of cold atom experiments focused on fragile many-body phases relevant to quantum magnetism, artificial gauge fields, and topological matter.Comment: 8 pages, 4 figures, Supplemental material

A Unique Sequence Of Financial Accounting Courses Featuring Team Teaching, Linked Courses, Challenging Assignments, And Instruments For Evaluation And Assessment

The Department of Accounting at California State University Northridge (CSUN) has developed a unique sequence of courses  designed to ensure that accounting students are trained not only in technical accounting, but also acquire critical thinking, research and communication skills.  The courses have proven effective and have embedded assessment measures that are used to evaluate and document student progress.  The assessment measures also provide feedback to faculty and have led to numerous improvements over time.  The Intermediate Accounting Sequence begins with a one (semester) unit bridge course that reviews the lower-division accounting material, introduces intermediate accounting concepts, and provides a base measure of students’ communication skills through a writing assignment.  The next three-unit intermediate accounting course (ACCT351) is linked with a two-unit accounting communication course (351COM).  These linked courses share unstructured case assignments written by the accounting faculty that require students to identify the accounting issue(s), research the authoritative literature in GAAP, and write a professional one-page document for each case that demonstrates critical thinking and appropriate documentation.  The structure of the linked courses is based on team work, and has the indirect benefit of promoting collegiality among faculty and fostering a culture of critical thinking throughout the accounting program. The skills acquired in 351/351COM are reinforced in subsequent courses through the use of similar assignments and evaluation and assessmen

Saks And The Unholy Trinity: Vendors, The Securities And Exchange Commission, And The Hedge Fund

This paper reports on the use of an unstructured case to teach and assess research, critical thinking, and communication skills in Intermediate Accounting classes.  It includes a case specifically prepared for this purpose (an imbedded course measure) and a generic critical thinking assessment form that was customized for this assignment.  This assessment process meets AACSB accreditation requirements.  Students satisfactorily determined relevant facts, identified the accounting issues, and supported solutions.  However, they did not satisfactorily research the authoritative literature or identify appropriate solutions

Differential Light Shift Cancellation in a Magnetic-Field-Insensitive Transition of 87^{87}Rb

We demonstrate near-complete cancellation of the differential light shift of a two-photon magnetic-field-insensitive microwave hyperfine (clock) transition in $^{87}$Rb atoms trapped in an optical lattice. Up to $95(2)$ of the differential light shift is canceled while maintaining magnetic-field insensitivity. This technique should have applications in quantum information and frequency metrology.Comment: 5 pages, 4 figure

SRB thermal curtain design support

Improvements in SRB Thermal Curtain were identified by thermal design featuring: selection of materials capable of thermal protection and service temperatures by tri-layering quartz, S2 glass, and Kevlar in thinner cross section; weaving in single piece (instead of 24 sections) to achieve improved strength; and weaving to reduce manufacturing cost with angle interlock construction

Repeated Measurements with Minimally Destructive Partial-Transfer Absorption Imaging

We demonstrate partial-transfer absorption imaging as a technique for repeatedly imaging an ultracold atomic ensemble with minimal perturbation. We prepare an atomic cloud in a state that is dark to the imaging light. We then use a microwave pulse to coherently transfer a small fraction of the ensemble to a bright state, which we image using in situ absorption imaging. The amplitude or duration of the microwave pulse controls the fractional transfer from the dark to the bright state. For small transfer fractions, we can image the atomic cloud up to 50 times before it is depleted. As a sample application, we repeatedly image an atomic cloud oscillating in a dipole trap to measure the trap frequency

Tonic and Phasic Amperometric Monitoring of Dopamine Using Microelectrode Arrays in Rat Striatum

Here we report a novel microelectrode array recording approach to measure tonic (resting) and phasic release of dopamine (DA) in DA-rich areas such as the rat striatum and nucleus accumbens. The resulting method is tested in intact central nervous system (CNS) and in animals with extensive loss of the DA pathway using the neurotoxin, 6-hydroxyDA (6-OHDA). The self-referencing amperometric recording method employs Nafion-coated with and without m-phenylenediamine recording sites that through real-time subtraction allow for simultaneous measures of tonic DA levels and transient changes due to depolarization and amphetamine-induced release. The recording method achieves low-level measures of both tonic and phasic DA with decreased recording drift allowing for enhanced sensitivity normally not achieved with electrochemical sensors in vivo