Adding nonlinearity to an electromagnetic-magnonic quantum hybrid device

In this book, hybrid systems based on yttrium-iron-garnet (YIG), three dimensional microwave cavity resonators, and superconducting transmon qubits, are investigated by continuous wave and pulsed microwave spectroscopy. Limitations to the magnetic linewidth in the quantum regime are identified and coherent exchange between a magnon and a superconducting qubit are demonstrated. Finally, a first step towards a strongly coupled hybrid system containing all three components is demonstrated

Adding nonlinearity to an electromagnetic-magnonic quantum hybrid device

In this book, hybrid systems based on yttrium-iron-garnet (YIG), three dimensional microwave cavity resonators, and superconducting transmon qubits, are investigated by continuous wave and pulsed microwave spectroscopy. Limitations to the magnetic linewidth in the quantum regime are identified and coherent exchange between a magnon and a superconducting qubit are demonstrated. Finally, a first step towards a strongly coupled hybrid system containing all three components is demonstrated

Complex temperature dependence of coupling and dissipation of cavity-magnon polaritons from milliKelvin to room temperature

Hybridized magnonic-photonic systems are key components for future information processing technologies such as storage, manipulation or conversion of data both in the classical (mostly at room temperature) and quantum (cryogenic) regime. In this work, we investigate a YIG sphere coupled strongly to a microwave cavity over the full temperature range from $290\,\mathrm{K}$ down to $30\,\mathrm{mK}$. The cavity-magnon polaritons are studied from the classical to the quantum regime where the thermal energy is less than one resonant microwave quanta, i.e. at temperatures below $1\,\mathrm{K}$. We compare the temperature dependence of the coupling strength $g_{\rm{eff}}(T)$, describing the strength of coherent energy exchange between spin ensemble and cavity photon, to the temperature behavior of the saturation magnetization evolution $M_{\rm{s}}(T)$ and find strong deviations at low temperatures. The temperature dependence of magnonic disspation is governed at intermediate temperatures by rare earth impurity scattering leading to a strong peak at $40\,$K. The linewidth $\kappa_{\rm{m}}$ decreases to $1.2\,$MHz at $30\,$mK, making this system suitable as a building block for quantum electrodynamics experiments. We achieve an electromagnonic cooperativity in excess of $20$ over the entire temperature range, with values beyond $100$ in the milliKelvin regime as well as at room temperature. With our measurements, spectroscopy on strongly coupled magnon-photon systems is demonstrated as versatile tool for spin material studies over large temperature ranges. Key parameters are provided in a single measurement, thus simplifying investigations significantly.Comment: 10 pages , 9 figures in tota

Adding nonlinearity to an electromagnetic-magnonic quantum hybrid device

In this book, hybrid systems based on yttrium-iron-garnet (YIG), three dimensional microwave cavity resonators, and superconducting transmon qubits, are investigated by continuous wave and pulsed microwave spectroscopy. Limitations to the magnetic linewidth in the quantum regime are identified and coherent exchange between a magnon and a superconducting qubit are demonstrated. Finally, a first step towards a strongly coupled hybrid system containing all three components is demonstrated

Lactate and T 2 measurements of synovial aspirates at 1.5T: differentiation of septic from non-septic arthritis

Objective: The aim of this study was to differentiate septic from non-septic arthritis by measuring lactate concentration with 1H magnetic resonance spectroscopy (HMRS) and by estimating total protein content with the assessment of T 2 values. Materials and methods: In 30 patients with acute arthritis, synovial fluid was aspirated. Lactate concentrations were analyzed with single voxel HMRS at 1.5T. T 2 relaxation times were mapped with a multi-spin echo sequence. All samples underwent microbiological testing and routine laboratory analysis to quantify lactate concentration and total protein content. Values obtained in septic and non-septic arthritis were compared with a Mann-Whitney U test. Results: Synovial fluid from patients with septic arthritis (n = 10) had higher concentrations of lactate (11.4 ± 4.0mmol/L) and higher total protein content (51.8 ± 10.7g/L) than fluid obtained in non-septic arthritis (n = 20; 5.2 ± 1.1mmol/L and 40.4 ± 6.9g/L, respectively, p 6mmol/L) in combination with low T 2 values (<550ms) identify septic arthritis with a sensitivity of 70% and a specificity of 89%. Conclusion: Spectroscopic measurements of lactate concentration in combination with the estimation of protein content using T 2 may be of value in the differentiation of septic from non-septic arthriti

Transmon Qubit in a Magnetic Field: Evolution of Coherence and Transition Frequency

We report on spectroscopic and time-domain measurements on a fixed-frequency concentric transmon qubit in an applied in-plane magnetic field to explore its limits of magnetic field compatibility. We demonstrate quantum coherence of the qubit up to field values of $B={40}\,\mathrm{mT}$, even without an optimized chip design or material combination of the qubit. The dephasing rate $\Gamma_\varphi$ is shown to be not affected by the magnetic field in a broad range of the qubit transition frequency. For the evolution of the qubit transition frequency, we find the unintended second junction created in the shadow angle evaporation process to be non-negligible and deduce an analytic formula for the field-dependent qubit energies. We discuss the relevant field-dependent loss channels, which can not be distinguished by our measurements, inviting further theoretical and experimental investigation. Using well-known and well-studied standard components of the superconducting quantum architecture, we are able to reach a field regime relevant for quantum sensing and hybrid applications of magnetic spins and spin systems.Comment: 9 pages, 8 figure

Ultrasound for the evaluation of femoroacetabular impingement of the cam type. Diagnostic performance of qualitative criteria and alpha angle measurements

Objective: To develop and assess a technique to evaluate cam type femoroacetabular impingement (FAI) using ultrasound (US). Methods: Fifty patients (24 women, 26 men) were included (mean age: 39.1years; age range: 16-59). US images of the anterior and anterosuperior contour of the femoral neck were obtained and analysed in 50 patients. Non-spherical shape of the head-neck junction (cam deformity), bony protuberances at the femoral neck, shape of the femoral neck (waist deficiency) and alpha angle were assessed. Magnetic resonance (MR) arthrography served as the standard of reference. Diagnostic performance and receiver operating characteristics (ROC) curves were calculated. Results: Based on MR arthrography 28 patients had cam-type FAI. On US, an anterosuperior cam deformity was seen in 40/44 patients (Reader 1/Reader 2; sensitivity 93%/89%, specificity 36%/14%). A bony protuberance anterosuperiorly in 23/13 patients (sensitivity 71%/32%, specificity 86%/82%) and an anterosuperior waist deficiency in 19/35 patients (sensitivity 25%/54%, specificity 100%/54%). Sensitivity and specificity of the other criteria were lower than 70% (average of Reader 1 & 2). Conclusion: A technique to evaluate cam type FAI using US is presented. The detection of an anterosuperior cam deformity is sensitive, and presence of an anterosuperior bony protuberance is specific for cam FAI. Alpha angle measurements are not helpful in establishing the diagnosi

Improved visualization of collateral ligaments of the ankle: multiplanar reconstructions based on standard 2D turbo spin-echo MR images

The purpose of the study was to evaluate the visualization of the collateral ankle ligaments on multiplanar reconstructions (MPR) based on standard 2D turbo spin-echo images. Coronal and axial T2-weighted turbo spin-echo and MPR angled parallel to the course of the ligaments of 15 asymptomatic and 15 symptomatic ankles were separately analyzed by two musculoskeletal radiologists. Image quality was assessed in the asymptomatic ankles qualitatively. In the symptomatic ankles interobserver agreement and reader confidence was determined for each ligament. On MPR the tibionavicular and calcaneofibular ligaments were more commonly demonstrated on a single image than on standard MR images (reader 1: 13 versus 0, P=0.002; reader 2: 14 versus 1, P=0.001 and reader 1: 13 versus 2, P=0.001; reader 2: 14 versus 0, P<0.001). The tibionavicular ligament was considered to be better delineated on MPR by reader 1 (12 versus 3, P=0.031). In the symptomatic ankles, reader confidence was greater with MPR for all ligaments except for the tibiocalcanear ligament (both readers) and the anterior and posterior talofibular ligaments (for reader 2). Interobserver agreement was increased with MPR for the tibionavicular ligament. Multiplanar reconstructions of 2D turbo spin-echo images improve the visualization of the tibionavicular and calcaneofibular ligaments and strengthen diagnostic confidence for these ligament

CT-guided cervical nerve root injections: comparing the immediate post-injection anesthetic-related effects of the transforaminal injection with a new indirect technique

Objective: To describe an "indirect” cervical nerve root injection technique with a dorsal approach that should carry less inherent risk than the "direct” cervical transforaminal injection approach, and to compare the immediate post-injection results of the two procedures. Materials and methods: The indirect and direct cervical nerve root injection procedures are described in detail. Fifty-three consecutive patients receiving the indirect nerve root injections during 2009-2010 were age- and gender-matched to 53 patients who underwent direct transforaminal nerve root injections performed in 2006. Pain level data were collected immediately before and 20-30min after each procedure. The percentages of pain change in the two groups were compared using the unpaired Student'st test. Results: Fifty-two men (mean age 49) and 54 women (mean age 55) were included. The mean percentage of pain reduction for patients receiving indirect nerve root injections was 38.4% and for those undergoing the direct nerve root injections approach it was 43.2%. This was not significantly different (P = 0.455). No immediate or late adverse effects were reported after either injection procedure. Conclusions: The indirect cervical nerve root injection procedure is a potentially safer alternative to direct cervical transforaminal nerve root injections. The short-term pain reduction is similar using the two injection method

Detection and quantification of glenohumeral joint effusion: reliability of ultrasound

Objectives: To evaluate reliability of ultrasound for detection and quantification of glenohumeral joint effusion. Methods: With institutional review board approval and informed consent ultrasound of 30 consecutive patients before and after MR arthrography of the shoulder was performed. Presence and width of any anechoic collection was noted within various locations (biceps tendon sheath, subscapular recess (neutral position and internal rotation), posterior glenohumeral joint recess (neutral position and external rotation)). Injected fluid (8-12ml) into the glenohumeral joint served as gold-standard. Widths of anechoic collections were correlated (Spearman rank correlation) with injected fluid. Results: Glenohumeral anechoic collection was consistently seen in the posterior glenohumeral joint recess with the arm in external rotation (100%, 30/30), and in the biceps tendon sheath (97%, 29/30). Ultrasound was not sensitive at other locations (7%-17%). Mean width in anterior-posterior direction of anechoic collection in the posterior glenohumeral joint recess was 7mm (range: 3-18mm), 2mm (range: 1-7mm) in the biceps tendon sheath. Significant correlation (R = 0.390, p = 0.033) was found between width of anechoic collection and injected fluid in the posterior glenohumeral joint recess. Conclusions: Glenohumeral joint effusion can be detected and quantified most reliably in the posterior glenohumeral joint recess with the arm in external rotatio