Quantum Electro- and Acoustodynamics in Waveguides

The study of light-matter interaction in superconducting quantum circuits has seen remarkable progress over the last $20$ years. By engineering artificial atoms, novel quantum phenomena have been demonstrated, and old ideas have come into a new light. Beyond their application to basic science, the prospect of implementing large-scale quantum information processing with superconducting circuits has fueled a rapid development of surrounding technologies, with ever-increasing control over their behavior as a result. The field\u27s success stems primarily from the flexible design and strong non-linearity of the artificial atom, whose coherent interaction with both electrical and mechanical degrees of freedom has opened many doors for science. This thesis deals with the interaction between artificial atoms and quantum fields in one-dimensional waveguides. The waveguide represents a one-dimensional environment for the atom, which we use to study the properties of open quantum systems. All quantum systems are, in fact, open, and interactions between the system and its environment lead inevitably to a loss of energy and quantum coherence. A continuous loss of information into the environment is called a Markovian process. The work contained in this thesis indicates that deviations from a Markovian process can be detected in the steady state of driven systems. This could simplify the detection of non-Markovianity in open quantum systems, as no information about the system\u27s transient dynamics would be necessary.Specifically, this thesis considers both electromagnetic fields in microwave transmission lines and acoustic fields in the form of surface acoustic waves (SAWs) traveling on the surface of solids. The recent realization of artificial atoms interacting with acoustic waves has opened up a new research field called quantum acoustics. We have built a model of the interaction between atoms and SAWs that predicts the existence of a new regime where the atom forms its own cavity. Additionally, we have considered synthesizing electromagnetically induced transparency, a quantum optics phenomena in opaque media where the absorption of photons is canceled, in waveguides using multiple closely spaced two-level systems. Some of the work in this thesis represents experimental work done in collaboration. In the first experiment, we studied the routing of acoustic waves at the quantum level. In the other experiment, we demonstrated electromagnetically induced transparency by creating an effective $\Lambda$ system using a giant artificial atom. This thesis reviews the numerical techniques used to model these experiments

Non-Markovian Steady States of a Driven Two-Level System

We show that an open quantum system in a non-Markovian environment can reach steady states that it cannot reach in a Markovian environment. As these steady states are unique for the non-Markovian regime, they could offer a simple way of detecting non-Markovianity, as no information about the system\u27s transient dynamics is necessary. In particular, we study a driven two-level system (TLS) in a semi-infinite waveguide. Once the waveguide has been traced out, the TLS sees an environment with a distinct memory time. The memory time enters the equations as a time delay that can be varied to compare a Markovian to a non-Markovian environment. We find that some non-Markovian states show exotic behaviors such as population inversion and steady-state coherence beyond 1/8, neither of which is possible for a driven TLS in the Markovian regime, where the time delay is neglected. Additionally, we show how the coherence of quantum interference is affected by time delays in a driven system by extracting the effective Purcell-modified decay rate of a TLS in front of a mirror

Experimental Verification of a Control Algorithm for Nonlinear Systems

NOMENCLATURE ABSTRACT When using electrodynamic vibration exciters to excite structures, the actual force applied to the structure under test is the reaction force between the exciter and the structure. The magnitude and phase of the reaction force is dependent upon the characteristics of the structure and exciter. Therefore the quality of the reaction force i.e. the force applied on the structure depends on the relationship between the exciter and structure under test. Looking at the signal from the force transducer when exciting a structure with a sine wave, the signal will appear harmonically distorted within the regions of the resonance frequencies. This phenomenon is easily observed when performing tests on lightly damped structures. The harmonic distortion is a result of nonlinearities produced by the shaker when undergoing large-amplitude vibrations, at resonances. When dealing with non-linear structures, it's of great importance to be able to keep a constant force level as well as a non-distorted sine wave in order to get reliable results within the regions of the resonance frequencies. This paper presents the method and results from an experimental test creating a nondistorted excitation signal with constant force level

Association between pharmaceutical modulation of oestrogen in postmenopausal women in Sweden and death due to COVID-19 : a cohort study

Objective Determine whether augmentation of oestrogen in postmenopausal women decreases the risk of death following COVID-19. Design Nationwide registry-based study in Sweden based on registries from the Swedish Public Health Agency (all individuals who tested positive for SARS-CoV-2); Statistics Sweden (socioeconomical variables) and the National Board of Health and Welfare (causes of death). Participants Postmenopausal women between 50 and 80 years of age with verified COVID-19. Interventions Pharmaceutical modulation of oestrogen as defined by (1) women with previously diagnosed breast cancer and receiving endocrine therapy (decreased systemic oestrogen levels); (2) women receiving hormone replacement therapy (increased systemic oestrogen levels) and (3) a control group not fulfilling requirements for group 1 or 2 (postmenopausal oestrogen levels). Adjustments were made for potential confounders such as age, annual disposable income (richest group as the reference category), highest level of education (primary, secondary and tertiary (reference)) and the weighted Charlson Comorbidity Index (wCCI). Primary outcome measure Death following COVID-19. Results From a nationwide cohort consisting of 49 853 women diagnosed with COVID-19 between 4 February and 14 September 2020 in Sweden, 16 693 were between 50 and 80 years of age. We included 14 685 women in the study with 11 923 (81%) in the control group, 227 (2%) women in group 1 and 2535 (17%) women in group 2. The unadjusted ORs for death following COVID-19 were 2.35 (95% CI 1.51 to 3.65) for group 1 and 0.45 (0.34 to 0.6) for group 2. Only the adjusted OR for death remained significant for group 2 with OR 0.47 (0.34 to 0.63). Absolute risk of death was 4.6% for the control group vs 10.1% and 2.1%, for the decreased and increased oestrogen groups, respectively. The risk of death due to COVID-19 was significantly associated with: age, OR 1.15 (1.14 to 1.17); annual income, poorest 2.79 (1.96 to 3.97), poor 2.43 (91.71 to 3.46) and middle 1.64 (1.11 to 2.41); and education (primary 1.4 (1.07 to 1.81)) and wCCI 1.13 (1.1 to 1.16). Conclusions Oestrogen supplementation in postmenopausal women is associated with a decreased risk of dying from COVID-19 in this nationwide cohort study. These findings are limited by the retrospective and non-randomised design. Further randomised intervention trials are warranted.Peer reviewe

Stromal PDGFRβ Expression in Prostate Tumors and Non-Malignant Prostate Tissue Predicts Prostate Cancer Survival

Background: The identification of new prognostic markers for prostate cancer is highly warranted, since it is difficult to identify patients requiring curative treatment. Data from both experimental models and clinical samples have identified important functions of PDGFRb on pericytes and fibroblasts in the tumor stroma. Methodology/Principal Findings: In this study the prognostic significance of PDGFRb in prostate cancer stroma, and in matched non-malignant tissue, was evaluated with immunohistochemistry. PDGFRb expression was analyzed in normal and tumor stroma from more than 300 prostate cancer patients. High PDGFRb expression in tumor stroma was associated with large tumor size, advanced stage, high Gleason score and high vessel density. Perivascular PDGFRb staining in tumors was also correlated with high Gleason score. Correlations were also observed between PDGFRb status in tumor stroma and nonmalignant stroma. Similarly, high PDGFRb expression in adjacent non-malignant tissue stroma correlated with large tumor size, advanced stage, high Gleason score and proliferation in non-malignant epithelium. Interestingly, high levels of PDGFRb in the stroma of tumor and non-malignant tissue were associated with shorter cancer specific survival in prostate cancer patients. Conclusions/Significance: The study revealed a number of novel associations between stromal PDGFRb expression i

Heat driven transport in serial double quantum dot devices

Studies of thermally induced transport in nanostructures provide access to an exciting regime where fluctuations are relevant, enabling the investigation of fundamental thermodynamic concepts and the realization of thermal energy harvesters. We study a serial double quantum dot formed in an InAs/InP nanowire coupled to two electron reservoirs. By means of a specially designed local metallic joule-heater, the temperature of the phonon bath in the vicinity of the double quantum dot can be enhanced. This results in phonon-assisted transport, enabling the conversion of local heat into electrical power in a nano-sized heat engine. Simultaneously, the electron temperatures of the reservoirs are affected, resulting in conventional thermoelectric transport. By detailed modelling and experimentally tuning the interdot coupling we disentangle both effects. Furthermore, we show that phonon-assisted transport gives access to the energy of excited states. Our findings demonstrate the versatility of our design to study fluctuations and fundamental nanothermodynamics.Comment: 11 pages, 4 figures + S

Metabolic changes in summer active and anuric hibernating free-ranging brown bears (ursus arctos)

The brown bear (Ursus arctos) hibernates for 5 to 6 months each winter and during this time ingests no food or water and remains anuric and inactive. Despite these extreme conditions, bears do not develop azotemia and preserve their muscle and bone strength. To date most renal studies have been limited to small numbers of bears, often in captive environments. Sixteen free-ranging bears were darted and had blood drawn both during hibernation in winter and summer. Samples were collected for measurement of creatinine and urea, markers of inflammation, the calcium-phosphate axis, and nutritional parameters including amino acids. In winter the bear serum creatinine increased 2.5 fold despite a 2-fold decrease in urea, indicating a remarkable ability to recycle urea nitrogen during hibernation. During hibernation serum calcium remained constant despite a decrease in serum phosphate and a rise in FGF23 levels. Despite prolonged inactivity and reduced renal function, inflammation does not ensue and bears seem to have enhanced antioxidant defense mechanisms during hibernation. Nutrition parameters showed high fat stores, preserved amino acids and mild hyperglycemia during hibernation. While total, essential, non-essential and branched chain amino acids concentrations do not change during hibernation anorexia, changes in individual amino acids ornithine, citrulline and arginine indicate an active, although reduced urea cycle and nitrogen recycling to proteins. Serum uric acid and serum fructose levels were elevated in summer and changes between seasons were positively correlated. Further studies to understand how bears can prevent the development of uremia despite minimal renal function during hibernation could provide new therapeutic avenues for the treatment of human kidney disease

Towards phonon routing: controlling propagating acoustic waves in the quantum regime

We explore routing of propagating phonons in analogy with previous experiments on photons. Surface acoustic waves (SAWs) in the microwave regime are scattered by a superconducting transmon qubit. The transmon can be tuned on or off resonance with the incident SAW field using an external magnetic field or the Autler-Townes effect, and thus the reflection and transmission of the SAW field can be controlled in time. We observe 80% extinction in the transmission of the low power continuous signal and a 40 ns rise time of the router. The slow propagation speed of SAWs on solid surfaces allows for in-flight manipulations of the propagating phonons. The ability to route short, 100 ns, pulses enables new functionality, for instance to catch an acoustic phonon between two qubits and then release it in a controlled direction

Mental Health Among Patients with non-Hodgkin Lymphoma:a Danish Nationwide Study of Psychotropic Drug Use in 8,750Patients and 43,750 Matched Comparators

Psychological distress following cancer diagnosis may lead to mental health complications including depression and anxiety. Non‐Hodgkin lymphomas (NHLs) include indolent and aggressive subtypes for which treatment and prognosis differ widely. Incident use of psychotropic drugs (PDs—antidepressants, antipsychotics, and anxiolytics) and its correlation to lymphoma types can give insights into the psychological distress these patients endure. In this prospective matched cohort study, we used nationwide population‐based registries to investigate the cumulative risk of PD use in NHL patients compared to a sex‐ and age‐matched cohort from the Danish background population. In addition, contact patterns to psychiatric departments and incident intentional self‐harm or completed suicide were explored. In total, 8750 NHL patients and 43 750 matched comparators were included (median age 68; male:female ratio 1.6). Median follow‐up was 7.1 years. Two‐year cumulative risk of PD use was higher in NHL patients (16.4%) as compared to the matched comparators (5.1%, p < .01); patients with aggressive NHL subtypes had the highest incidence. Prescription rates were higher in the first years after diagnosis but approached the rate of the matched population 5 years into survivorship in aggressive NHLs, whereas patients with indolent subtypes continued to be at higher risk. NHL patients had a slightly higher two‐year risk of suicide/intentional self‐harm (0.3%) as compared to the matched comparators (0.2%, p = .01). These results demonstrate that mental health complications among NHL patients are frequent. Routine assessment for symptoms of depression and anxiety should be consider as part of standard follow‐up of NHL patients

Stirring the motivational soup: Within-person latent profiles of motivation in exercise

Background: The purpose of the present study was to use a person-oriented analytical approach to identify latent motivational profiles, based on the different behavioural regulations for exercise, and to examine differences in satisfaction of basic psychological needs (competence, autonomy and relatedness) and exercise behaviour across these motivational profiles. Methods: Two samples, consisting of 1084 and 511 adults respectively, completed exercise-related measures of behavioural regulation and psychological need satisfaction as well as exercise behaviour. Latent profile analyses were used to identify motivational profiles. Results: Six profiles, representing different combinations of regulations for exercise, were found to best represent data in both samples. Some profiles were found in both samples (e.g., low motivation profile, self-determined motivation profile and self-determined with high introjected regulation profile), whereas others were unique to each sample. In line with the Self-Determination Theory, individuals belonging to more self-determined profiles demonstrated higher scores on need satisfaction. Conclusions: The results support the notions of motivation being a multidimensional construct and that people have different, sometimes competing, reasons for engaging in exercise. The benefits of using person-oriented analyses to examine within-person interactions of motivation and different regulations are discussed. © 2017 The Author(s)