Deterministic quantum state transfer and remote entanglement using microwave photons.

Sharing information coherently between nodes of a quantum network is fundamental to distributed quantum information processing. In this scheme, the computation is divided into subroutines and performed on several smaller quantum registers that are connected by classical and quantum channels 1 . A direct quantum channel, which connects nodes deterministically rather than probabilistically, achieves larger entanglement rates between nodes and is advantageous for distributed fault-tolerant quantum computation 2 . Here we implement deterministic state-transfer and entanglement protocols between two superconducting qubits fabricated on separate chips. Superconducting circuits 3 constitute a universal quantum node 4 that is capable of sending, receiving, storing and processing quantum information5-8. Our implementation is based on an all-microwave cavity-assisted Raman process 9 , which entangles or transfers the qubit state of a transmon-type artificial atom 10 with a time-symmetric itinerant single photon. We transfer qubit states by absorbing these itinerant photons at the receiving node, with a probability of 98.1 ± 0.1 per cent, achieving a transfer-process fidelity of 80.02 ± 0.07 per cent for a protocol duration of only 180 nanoseconds. We also prepare remote entanglement on demand with a fidelity as high as 78.9 ± 0.1 per cent at a rate of 50 kilohertz. Our results are in excellent agreement with numerical simulations based on a master-equation description of the system. This deterministic protocol has the potential to be used for quantum computing distributed across different nodes of a cryogenic network.

Microwave Quantum Link between Superconducting Circuits Housed in Spatially Separated Cryogenic Systems.

Superconducting circuits are a strong contender for realizing quantum computing systems and are also successfully used to study quantum optics and hybrid quantum systems. However, their cryogenic operation temperatures and the current lack of coherence-preserving microwave-to-optical conversion solutions have hindered the realization of superconducting quantum networks spanning different cryogenic systems or larger distances. Here, we report the successful operation of a cryogenic waveguide coherently linking transmon qubits located in two dilution refrigerators separated by a physical distance of five meters. We transfer qubit states and generate entanglement on demand with average transfer and target state fidelities of 85.8% and 79.5%, respectively, between the two nodes of this elementary network. Cryogenic microwave links provide an opportunity to scale up systems for quantum computing and create local area superconducting quantum communication networks over length scales of at least tens of meters.

[Everyday relevance of APHAB questions : Influence on answer frequency]. / Alltagsrelevanz der APHAB-Fragen : Einfluss auf die Beantwortungshäufigkeit.

BACKGROUND: The Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire measures subjective hearing impairment in different situations. Recently, a survey demonstrated that some APHAB questions were answered more rarely than others. This study aims to evaluate the everyday relevance of each APHAB question and investigate whether this relevance for daily life influences answer frequency. METHODS: Between July 2016 and November 2017, 517 hearing impaired patients from 11 ENT practices in Schleswig-Holstein, Germany, were evaluated using the APHAB. In parallel, the everyday relevance of each APHAB question for the subjects was assessed on a four-step scale (often/sometimes/rarely/never). The answers were listed in a cross table and statistically analyzed. RESULTS: The average age of all subjects was 67.4 years (±14.0 years); 45.3% were female and 54.7% were male. One APHAB question (no. 21) was answered noticeably less often than the others. Overall, five types of distribution for the everyday relevance of APHAB questions could be determined. Using the χ2-test, no correlation between the frequency of answers and their everyday relevance could be detected (p < 0.001). CONCLUSION: No correlation between everyday relevance and answer frequency was detected. However, the five types of distribution could be used for an individual interpretation of single APHAB answers. In the future, a possible influence of everyday relevance on ranking within a specific APHAB answer should be investigated.

Fast and Unconditional All-Microwave Reset of a Superconducting Qubit.

Active qubit reset is a key operation in many quantum algorithms, and particularly in quantum error correction. Here, we experimentally demonstrate a reset scheme for a three-level transmon artificial atom coupled to a large bandwidth resonator. The reset protocol uses a microwave-induced interaction between the |f,0⟩ and |g,1⟩ states of the coupled transmon-resonator system, with |g⟩ and |f⟩ denoting the ground and second excited states of the transmon, and |0⟩ and |1⟩ the photon Fock states of the resonator. We characterize the reset process and demonstrate reinitialization of the transmon-resonator system to its ground state in less than 500 ns and with 0.2% residual excitation. Our protocol is of practical interest as it has no additional architectural requirements beyond those needed for fast and efficient single-shot readout of transmons, and does not require feedback.

Impaired psychometric testing in polyglandular autoimmunity.

OBJECTIVE: Patients with the autoimmune polyglandular syndrome (APS) could be exposed to many limitations in daily life owing to their illness. To quantify the degree of physical and emotional distress, the psychometric profile of these patients was evaluated prospectively. DESIGN, PATIENTS AND MEASUREMENTS: After a complete endocrine investigation, three international validated self-assessment questionnaires were applied in 75 patients with APS: the health-related quality of life Short-Form 36 (SF-36), the Giessen Complaint List (GBB-24) and the Hospital Anxiety and Depression Scale (HADS). RESULTS: Average duration of APS was 7.7 years. The most frequent disease combination was type 1 diabetes and autoimmune thyroid disease (n=47, 62.6%). Every scale of the SF-36, GBB-24, and the HADS anxiety score demonstrated markedly impaired physical and emotional well-being, foremost in female subjects (P<0.001). Compared to a German reference cohort, all subscales of the SF-36 were decreased (P<0.001). Sex- and age-matched z-scores were significantly lower for physical functioning (-1.1; reference population z=0), physical role limitations (-0.8), bodily pain (-0.7), general health perception (-1.2), vitality (-0.8), social functioning (-0.8), emotional role limitations (-1.1) and mental health (-0.5). Also, the global score of discomfort was increased in comparison with the reference population (27.27 vs 13.93, P<0.001). Generalized anxiety (25%, P<0.001) and depression episode (18.1%, P<0.001) were prevalent in APS. Neither time interval between two endocrine diseases, duration of APS, age, nor autoantibody positivity influenced psychometric testing results. CONCLUSION: Patients with APS have a severely impaired psychometric profile. Treatment modalities that would improve their well-being are warranted.

[The polyglandular autoimmune syndrome--quality of life and family clustering]. / Das polyglanduläre Autoimmunsyndrom--Lebensqualität und familiäre Beteiligung.

BACKGROUND AND AIM: For patients with polyglandular autoimmune syndrome (PGA), data pertaining to familial clustering and quality of life are missing. Therefore, we performed a prospective and controlled study to collect this information. PATIENTS AND METHODS: Clinical and serological evaluation of 75 consecutively recruited patients with PGA (mean age 47,5 ± 15,3 years; 65,3% women) and their 108 relatives (mean age 33,13 ± 20,08 years; 65,7% women) was performed. Three validated questionnaires for psychosocial evaluation (quality of life short form 36 [SF-36], hospital anxiety and depression scale [HADS] and the Gießener Beschwerdebogen [GBB]) were answered by patients and relatives. RESULTS: 47 (62%) patients with PGA had type 1 diabetes and autoimmune thyroid disease. 56 (52%) of their relatives had an autoimmune disease whereas Hashimoto's thyroiditis and type-A-gastritis were the most prevalent endocrine and non-endocrine components. Thyroid peroxidase autoantibodies were most prevalent in patients and involved relatives. Compared to a German reference group, all scales of the SF-36 were markedly decreased in patients and involved relatives (p < 0.001). Anxiety and depression scales were pathologically increased in patients and relatives (p < 0.001). Also, all GBB scales were elevated for patients and relatives (p < 0.001). Patients with both glandular and non-glandular autoimmune diseases showed the most pathological psychosocial results. CONCLUSION: Familial clustering is high in patients with PGA. Quality of life and psychosocial status are poor in patients and involved relatives. Multidisciplinary management of the multiplex families in specialized centers is warranted.

[Experiences with a hydroxyapatite-coated, macroporous surface hip endoprosthesis]. / Erfahrungen mit einer Hydroxylapatit-beschichteten, makroporös strukturierten Hüftendoprothese.

INTRODUCTION: Cementless hip arthroplasty is not completely satisfactory--even with macroporous structured surface. Medium term results are sometimes disappointing because of insufficient secondary stability. Thus our aim was to improve fixation by additional coating with hydroxyapatite. METHODS: 200 consecutive patients who had hydroxyapatite-coated cementless hip replacement with a macroporous hip prosthesis (09/92-03/96) were studied prospectively. All patients were included in a prospective follow up schedule according to the criteria of Johnston et al. As measure of clinical outcome we calculated Harris Hip Score as well as Enghs Score to assess radiologic fixation and stability. RESULTS: 91% could be followed up regularly. No revision because of aseptic loosening had to be done. Analysis of clinical results showed almost painless patients from early after the operation--especially no thigh pain. Average HHS after 2 years was 97. Radiological evaluation showed early and complete osteointegration of all components. According to Engh-Score they are stable and well fixed. CONCLUSION: HA coated macroporous implants provide some striking advantages, which encouraged us to continue with this system. By early and secure bony ingrowth a fibrous interface is avoided and thereby also long-lasting thigh pain.

Traumatic events and post-traumatic stress disorder in the community: prevalence, risk factors and comorbidity.

OBJECTIVE: Lifetime and 12-month prevalence of traumatic events and DSM-IV post-traumatic stress disorder as well as risk factors and comorbidity patterns were investigated in a representative community sample (n = 3021, aged 14-24 years). METHOD: Traumatic events and PTSD were assessed with the Munich Composite International Diagnostic Interview (CIDI). RESULTS: Although 26% of male subjects and 17.7% of female subjects reported at least one traumatic event, only a few qualified for a full PTSD diagnosis (1% of males and 2.2% of females). Traumatic events and PTSD were strongly associated with all other mental disorders examined. PTSD occurred as both a primary and a secondary disorder. CONCLUSION: The prevalence of PTSD in this young German sample is considerably lower than reported in previous US studies. However, the conditional probability for PTSD after experiencing traumas, risk factors and comorbidity patterns are quite similar. Traumatic events and full PTSD may increase the risk for other disorders, and vice versa.