Optimal control for one-qubit quantum sensing

Quantum systems can be exquisite sensors thanks to their sensitivity to external perturbations. This same characteristic also makes them fragile to external noise. Quantum control can tackle the challenge of protecting quantum sensors from environmental noise, while leaving their strong coupling to the target field to be measured. As the compromise between these two conflicting requirements does not always have an intuitive solution, optimal control based on numerical search could prove very effective. Here we adapt optimal control theory to the quantum sensing scenario, by introducing a cost function that, unlike the usual fidelity of operation, correctly takes into account both the unknown field to be measured and the environmental noise. We experimentally implement this novel control paradigm using a Nitrogen Vacancy center in diamond, finding improved sensitivity to a broad set of time varying fields. The demonstrated robustness and efficiency of the numerical optimization, as well as the sensitivity advantaged it bestows, will prove beneficial to many quantum sensing applications

Postprocessing Neuroimaging methods in MRI and PET/MRI with applications to Multiple Sclerosis and other Neurological diseases

Many non-invasive imaging instruments have been developed in the last 40 years, allowing to obtain images of the interior human body while the patient is still alive. In the contest of Neurology studies, imaging system as CT, MRI, SPECT or PET allows to obtain biomarkers useful to quantitatively distinguish between healthy and unhealthy subjects, evaluate the staging of a Neurological illness in a patient, evaluate the efficacy of a treatment, explore the causes of the illness. In this work MRI and PET imaging system introduced from scratch, going from reconstruction from raw data to state-of-the art post-processing techniques and the computation of more popular biomarkers. After these introduction, three original work using the recent PET/MRI imaging system are presented, with a particular focus on the methods. These three studies involve patients with Multiple Sclerosis, Alzheimer's Disease and Brain Tumor

Student responses to an animated character in information literacy instruction

Purpose: This paper reports on a grant-funded project to create a hand-drawn, custom-made animated character named Jasmyn. Drawing on animation theory, the paper uses qualitative research to investigate student responses to the medium of animation, the character’s design, and three presentation strategies. Design/methodology/approach: The researchers held three student focus groups to investigate the following research questions: 1. Will students endorse animation as a medium for library instructional videos on the grounds of its entertaining, subversive, or playful qualities? 2. Is Jasmyn designed and8 written in a way that engages students and compels them to respond to her as a character? 3. How will students respond to three presentation strategies: a lecture-style video, a video with supplemental animations, and a real-time, interactive lesson. Findings: The researchers found that students expressed broad enthusiasm for animation as a medium, though responses to Jasmyn’s personality were mixed. The only presentation strategy that prompted unique responses was the interactive session, although though all three focus groups provided revealing commentary about online learning. Students also identified aspects of the animation and character that could be improved, and reflected on ways Jasmyn might be integrated into online learning. Research limitations/implications: This study, performed as part of a pilot project, was deliberately small in scale. Clearer implications would emerge from repetition with a larger group of students. Originality/value: Jasmyn may be the only hand-drawn, custom-made animated character created for library instruction. No research studies on the use of animation in libraries have been published to date

Noise spectroscopy of a quantum-classical environment with a diamond qubit

Knowing a quantum system's environment is critical for its practical use as a quantum device. Qubit sensors can reconstruct the noise spectral density of a classical bath, provided long enough coherence time. Here we present a protocol that can unravel the characteristics of a more complex environment, comprising both unknown coherently coupled quantum systems, and a larger quantum bath that can be modeled as a classical stochastic field. We exploit the rich environment of a Nitrogen-Vacancy center in diamond, tuning the environment behavior with a bias magnetic field, to experimentally demonstrate our method. We show how to reconstruct the noise spectral density even when limited by relatively short coherence times, and identify the local spin environment. Importantly, we demonstrate that the reconstructed model can have predictive power, describing the spin qubit dynamics under control sequences not used for noise spectroscopy, a feature critical for building robust quantum devices. At lower bias fields, where the effects of the quantum nature of the bath are more pronounced, we find that more than a single classical noise model are needed to properly describe the spin coherence under different controls, due to the back action of the qubit onto the bath.Comment: Main text: 5 pages, 5 figures. Supplemental material: 7 pages, 7 figures, 4 table

Comics to the Rescue: Finding Innovative Applications for Library Digital Learning Objects

When faculty were asked to use online assignments to make up the class time lost due to Hurricane Sandy, librarians at Lehman College\u27s Leonard Lief Library spotted a new opportunity for the Library\u27s Web comics. This article describes the partnership between the Library and the College\u27s Art Department that led to the development of the Web comics, provides readers with a model for responding to circumstances creatively, and puts forward an approach for combining digital learning objects with writing assignments to meet faculty needs

A Low-Hassle, Low-Cost Method to Survey Student Attitudes about Library Space

This article discusses how two members of the space planning committee at Lehman College library created a brief paper survey, distributed it to students in the library, and designed a Google spreadsheet to enable the committee to work as a group to compile results. We provide our survey tool as an example; explain how we simplified data compilation through a “quick and dirty” coding process; outline step-by-step instructions on how to design a Google spreadsheet that enables many librarians to input survey results consistently; and describe our mistakes and “lessons learned.” We believe our practical approach could be easily implemented as a space planning tool in any number of libraries—even those with small staffs and budgets