Reservoir-Free Decoherence in Flying Qubits.

An effective time-dependent Hamiltonian can be implemented by making a quantum system fly through an inhomogeneous potential, realizing, for example, a quantum gate on its internal degrees of freedom. However, flying systems have a spatial spread that will generically entangle the internal and spatial degrees of freedom, leading to decoherence in the internal state dynamics, even in the absence of any external reservoir. We provide formulas valid at all times for the dynamics, fidelity, and change of entropy for ballistic particles with small spatial spreads, quantified by Δx. This non-Markovian decoherence can be significant for ballistic flying qubits (scaling as Δx^{2}) but usually not for flying qubits carried by a moving potential well (scaling as Δx^{6}). We also discuss a method to completely counteract this decoherence for a ballistic qubit later measured.

Isolated Tricuspid Valve Surgery for Functional Tricuspid Regurgitation.

BACKGROUND: Severe tricuspid regurgitation (TR) adversely affects long-term survival; however, isolated tricuspid valve (TV) surgery has been rarely performed due to high operative mortality. In addition, the previous literature included heterogeneous TR etiologies. Therefore, we aimed to elucidate early and long-term outcomes of isolated TV surgery for functional TR. METHODS: An electronic search was performed to identify all relevant studies. Baseline characteristics, perioperative variables, and clinical outcomes were extracted and pooled for meta-analysis. RESULTS: This meta-analysis included seven studies. Pooled analyses showed that 68% (35, 89) of patients had preoperative atrial fibrillation or flutter, and 58% (11, 94) had a history of left-sided valve surgery. Seventy-three percent (65, 80) of patients had at least one physical exam finding of right-sided heart failure, and 57% (44, 69) were in New York Heart Association class III or IV. TV replacement was more common than repair. In TV replacement, bioprosthetic valve (39%, 13, 74) was more common than mechanical prosthesis (22%, 18, 26). The early mortality rate was 7%. Twenty percent of patients required a permanent pacemaker postoperatively. The overall 1- and 5-year survival rates were 84.5 and 69.1%, respectively. CONCLUSION: More than half of the patients who underwent isolated TV surgery for functional TR had undergone left-sided valve surgery and had significant heart failure symptoms at the time of surgery. Further studies on the surgical indication for concomitant TV surgery at the time of left-sided valve surgery and the appropriate timing of surgery for isolated functional TR are needed to improve survival.

Neutrophil-to-lymphocyte ratio and all-cause mortality with and without myeloproliferative neoplasms-a Danish longitudinal study.

The neutrophil-to-lymphocyte ratio(NLR) is increased in chronic inflammation and myeloproliferative neoplasms (MPN). We hypothesize that NLR is associated with all-cause mortality and mortality by comorbidity burden in the general population and individuals with MPN. We included 835,430 individuals from The Danish General Suburban Population Study, general practitioners, and outpatient clinics. We investigated NLR on mortality stratified by prevalent and incident MPN, essential thrombocythemia (ET), polycythemia vera (PV), myelofibrosis (MF), comorbidity burden (CCI-score), and the Triple-A risk score using hazard ratio (HR) and 95% confidence interval (95%CI). NLR 1-1.9 was the reference level. During a median follow-up of 11.2 years, 197,802 deaths were recorded. All-cause mortality increased for a stepwise increasing NLR with a HR (95%CI) for NLR ≥ 6 of 2.06(2.03-2.09) for the whole population and 2.93(2.44-3.50) in prevalent MPN. ET, PV, and MF had a HR (95%CI) for NLR ≥ 2 of 2.14(1.71-2.69), 2.19(1.89-2.54), and 2.31(1.91-2.80). Results were similar for incident MPN. Mortality was higher for stepwise increasing NLR and CCI-score(pinteraction < 2×10-16), with a HR for NLR ≥ 6 of 2.23(2.17-2.29), 4.10(4.01-4.20), and 7.69(7.50-7.89), for CCI-score 0, 1-2, or ≥3. The Triple-A risk score demonstrated alignment with NLR. Increasing NLR and comorbidity burden were associated with lower survival in individuals without MPN but were even worse in prevalent and incident MPN, ET, PV, and MF.

Mapping the phase-separated state in a 2D magnet.

Intrinsic 2D magnets have recently been established as a playground for studies on fundamentals of magnetism, quantum phases, and spintronic applications. The inherent instability at low dimensionality often results in coexistence and/or competition of different magnetic orders. Such instability of magnetic ordering may manifest itself as phase-separated states. In 4f 2D materials, magnetic phase separation is expressed in various experiments; however, the experimental evidence is circumstantial. Here, we employ a high-sensitivity MFM technique to probe the spatial distribution of magnetic states in the paradigmatic 4f 2D ferromagnet EuGe2. Below the ferromagnetic transition temperature, we discover the phase-separated state and follow its evolution with temperature and magnetic field. The characteristic length-scale of magnetic domains amounts to hundreds of nanometers. These observations strongly shape our understanding of the magnetic states in 2D materials at the monolayer limit and contribute to engineering of ultra-compact spintronics.

Supergrowth and sub-wavelength object imaging.

We further develop the concept of supergrowth [Quantum Stud.: Math. Found.7, 285 (2020)10.1007/s40509-019-00214-5], a phenomenon complementary to superoscillation, defined as the local amplitude growth rate of a function higher than its largest wavenumber. We identify a canonical oscillatory function's superoscillating and supergrowing regions and find the maximum values of local growth rate and wavenumber. Next, we provide a quantitative comparison of lengths and relevant intensities between the superoscillating and the supergrowing regions of a canonical oscillatory function. Our analysis shows that the supergrowing regions contain intensities that are exponentially larger in terms of the highest local wavenumber compared to the superoscillating regions. Finally, we prescribe methods to reconstruct a sub-wavelength object from the imaging data using both superoscillatory and supergrowing point spread functions. Our investigation provides an experimentally preferable alternative to the superoscillation-based superresolution schemes and is relevant to cutting-edge research in far-field sub-wavelength imaging.

Super Interferometric Range Resolution.

We probe the fundamental underpinnings of range resolution in coherent remote sensing. We use a novel class of self-referential interference functions to show that we can greatly improve upon currently accepted bounds for range resolution. We consider the range resolution problem from the perspective of single-parameter estimation of amplitude versus the traditional temporally resolved paradigm. We define two figures of merit: (i) the minimum resolvable distance between two depths and (ii) for temporally subresolved peaks, the depth resolution between the objects. We experimentally demonstrate that our system can resolve two depths greater than 100× the inverse bandwidth and measure the distance between two objects to approximately 20 µm (35 000 times smaller than the Rayleigh-resolved limit) for temporally subresolved objects using frequencies less than 120 MHz radio waves.

Novel Use of an Accelerometer to Assess Load Asymmetry Over Time After Hip Resurfacing Arthroplasty.

BACKGROUND: There is limited knowledge regarding usage of wearable technology to guide return to sport after hip resurfacing arthroplasty (HRA). This study evaluated the use of accelerometers to identify when symmetry is restored between operative and nonoperative limbs. METHODS: A total of 26 primary HRA patients performed 5 validated physical tests before, 3 and 6 months after HRA: broad jump, double-leg vertical jump (DLVJ), hop test, lateral single-leg jump (LSLJ), and vertical single-leg jump. Impact load and average intensity data (g-force units) were collected using accelerometers. Strength data (pounds [lbs.]) for internal and external rotation were collected with a dynamometer. Univariate and correlation analyses analyzed interlimb asymmetries. RESULTS: At preoperation, there were significant impact load asymmetries for DLVJ (P = .008), hop test (P = .021), and LSLJ (P = .003) and intensity asymmetry for DLVJ (P = .010) and LSLJ (P = .003). At 3 months, there was impact load asymmetry for DLVJ (P = .005) and LSLJ (P = .005) and intensity asymmetry for broad jump (P = .020), hop test (P = .042), and LSLJ (P = .005). There were significant strength asymmetries at preoperation and 3 months postoperation for internal (P = .013) and external rotation (P = .037). All significant asymmetries indicated the nonoperative leg had greater output. No significant asymmetries were found for any exercises at 6 months postoperation. An increase in Harris Hip Score was significantly associated with a decrease in impact asymmetry (rs = -0.269, P = .006). CONCLUSION: Impact loads and strength reach interlimb symmetry at 6 months post-HRA. Wearable accelerometers provide useful metrics to distinguish limb asymmetries for recovery monitoring.

Measurement-Based Quantum Thermal Machines with Feedback Control.

We investigated coupled-qubit-based thermal machines powered by quantum measurements and feedback. We considered two different versions of the machine: (1) a quantum Maxwell's demon, where the coupled-qubit system is connected to a detachable single shared bath, and (2) a measurement-assisted refrigerator, where the coupled-qubit system is in contact with a hot and cold bath. In the quantum Maxwell's demon case, we discuss both discrete and continuous measurements. We found that the power output from a single qubit-based device can be improved by coupling it to the second qubit. We further found that the simultaneous measurement of both qubits can produce higher net heat extraction compared to two setups operated in parallel where only single-qubit measurements are performed. In the refrigerator case, we used continuous measurement and unitary operations to power the coupled-qubit-based refrigerator. We found that the cooling power of a refrigerator operated with swap operations can be enhanced by performing suitable measurements.

Bronchial artery revascularization in lung transplantation: a systematic review and meta-analysis.

Background: Bronchial artery revascularization (BAR) during lung transplantation has been hypothesized to improve early tracheal healing and delay the onset of bronchiolitis obliterans syndrome (BOS). We aimed to assess the outcomes of BAR after lung transplantation. Methods: Electronic search in Ovid Medline, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Scopus, and Cochrane Controlled Trials Register (CCTR) databases was performed to identify all relevant studies published about lung transplantation with BAR. Studies discussing lung transplantation utilizing BAR were included while those without outcome data such as BOS and survival were excluded. Cohort-level data were extracted and pooled for analysis. A binary outcome meta-analysis of proportions with logit transformation was conducted. Newcastle-Ottawa scale was used for risk of bias assessment. Results: Seven studies were selected for the analysis comprising 143 patients. Mean patient age was 47 (95% CI: 40-55) years. Sixty-one percent (48-72%) were male. Seventy-three percent (65-79%) of patients underwent double lung transplant while 27% (21-25%) underwent single lung transplant. In patients with postoperative angiography, successful BAR was demonstrated in 93% (82-97%) of all assessed conduits. The 30-day/in-hospital mortality was 6% (3-11%). Seventy-nine percent (63-89%) of patients were free from rejection at three months. Eighty-three percent (29-98%) of patients were free from signs of airway ischemia at three and six months. Pooled survival at one year and five years was 87% (78-92%) and 71% (46-87%), respectively, with a mean follow-up time of 21 (3-38) months. Pooled freedom from bronchiolitis obliterans was 86% (77-91%) at two years. Conclusions: While this systematic review and meta-analysis is limited by the available surgeons, institutions, and papers discussing a highly specialized technique, it does show that BAR is a viable technique to minimize BOS and early anastomotic intervention following lung transplantation.

Nuclear magnetic resonance diffraction with subangstrom precision.

We have combined ultrasensitive force-based spin detection with high-fidelity spin control to achieve NMR diffraction (NMRd) measurement of ~2 million [Formula: see text]P spins in a [Formula: see text] volume of an indium-phosphide (InP) nanowire. NMRd is a technique originally proposed for studying the structure of periodic arrangements of spins, with complete access to the spectroscopic capabilities of NMR. We describe two experiments that realize NMRd detection with subangstrom precision. In the first experiment, we encode a nanometer-scale spatial modulation of the z-axis magnetization of [Formula: see text]P spins and detect the period and position of the modulation with a precision of <0.8 Å. In the second experiment, we demonstrate an interferometric technique, utilizing NMRd, to detect an angstrom-scale displacement of the InP sample with a precision of 0.07 Å. The diffraction-based techniques developed in this work extend the Fourier-encoding capabilities of NMR to the angstrom scale and demonstrate the potential of NMRd as a tool for probing the structure and dynamics of nanocrystalline materials.

Energetic Cost of Measurements Using Quantum, Coherent, and Thermal Light.

Quantum measurements are basic operations that play a critical role in the study and application of quantum information. We study how the use of quantum, coherent, and classical thermal states of light in a circuit quantum electrodynamics setup impacts the performance of quantum measurements, by comparing their respective measurement backaction and measurement signal to noise ratio per photon. In the strong dispersive limit, we find that thermal light is capable of performing quantum measurements with comparable efficiency to coherent light, both being outperformed by single-photon light. We then analyze the thermodynamic cost of each measurement scheme. We show that single-photon light shows an advantage in terms of energy cost per information gain, reaching the fundamental thermodynamic cost.

Efficiently fueling a quantum engine with incompatible measurements.

We propose a quantum harmonic oscillator measurement engine fueled by simultaneous quantum measurements of the noncommuting position and momentum quadratures of the quantum oscillator. The engine extracts work by moving the harmonic trap suddenly, conditioned on the measurement outcomes. We present two protocols for work extraction, respectively based on single-shot and time-continuous quantum measurements. In the single-shot limit, the oscillator is measured in a coherent state basis; the measurement adds an average of one quantum of energy to the oscillator, which is then extracted in the feedback step. In the time-continuous limit, continuous weak quantum measurements of both position and momentum of the quantum oscillator result in a coherent state, whose coordinates diffuse in time. We relate the extractable work to the noise added by quadrature measurements, and present exact results for the work distribution at arbitrary finite time. Both protocols can achieve unit work conversion efficiency in principle.

Variational Principle for Optimal Quantum Controls in Quantum Metrology.

We develop a variational principle to determine the quantum controls and initial state that optimizes the quantum Fisher information, the quantity characterizing the precision in quantum metrology. When the set of available controls is limited, the exact optimal initial state and the optimal controls are, in general, dependent on the probe time, a feature missing in the unrestricted case. Yet, for time-independent Hamiltonians with restricted controls, the problem can be approximately reduced to the unconstrained case via Floquet engineering. In particular, we find for magnetometry with a time-independent spin chain containing three-body interactions, even when the controls are restricted to one- and two-body interaction, that the Heisenberg scaling can still be approximately achieved. Our results open the door to investigate quantum metrology under a limited set of available controls, of relevance to many-body quantum metrology in realistic scenarios.

Experimental demonstration of continuous quantum error correction.

The storage and processing of quantum information are susceptible to external noise, resulting in computational errors. A powerful method to suppress these effects is quantum error correction. Typically, quantum error correction is executed in discrete rounds, using entangling gates and projective measurement on ancillary qubits to complete each round of error correction. Here we use direct parity measurements to implement a continuous quantum bit-flip correction code in a resource-efficient manner, eliminating entangling gates, ancillary qubits, and their associated errors. An FPGA controller actively corrects errors as they are detected, achieving an average bit-flip detection efficiency of up to 91%. Furthermore, the protocol increases the relaxation time of the protected logical qubit by a factor of 2.7 over the relaxation times of the bare comprising qubits. Our results showcase resource-efficient stabilizer measurements in a multi-qubit architecture and demonstrate how continuous error correction codes can address challenges in realizing a fault-tolerant system.

Cross-cultural adaptation of the Spanish MINICHAL instrument into English for use in the United Kingdom.

BACKGROUND: Hypertension is a highly prevalent condition, with optimal treatment to BP targets conferring significant gains in terms of cardiovascular outcomes. Understanding why some patients do not achieve BP targets would be enhanced through greater understanding of their health-related quality of life (HRQoL). However, the only English language disease-specific instruments for measurement of HRQoL in hypertension have not been validated in accordance with accepted standards. It is proposed that the Spanish MINICHAL instrument for the assessment of HRQoL in hypertension could be translated, adapted and validated for use in the United Kingdom. The aim of the study was therefore to complete this process. METHODS: The MINICHAL authors were contacted and the original instrument obtained. This was then translated into English by two independent English-speakers, with these versions then reconciled, before back-translation and subsequent production of a 2nd reconciled version. Thereafter, a final version was produced after cognitive debriefing, for administration and psychometric analysis in the target population of patients living in the Exeter area (Southwest UK) aged 18-80 years with treatment-naïve grade II-III hypertension, before, during and after 18 weeks' intensive treatment. RESULTS: The English-language instrument was administered to 30 individuals (median age: 58.5 years, 53% male). Psychometric analysis demonstrated a floor effect, though no ceiling effect. Internal consistency for both state of mind (StM) and somatic manifestations (SM) dimensions of the instrument were acceptable (Cronbach's alpha = 0.81 and 0.75), as was test-retest reliability (ICC = 0.717 and 0.961) and construct validity, which was measured through co-administration with the EQ-5D-5L and Bulpitt-Fletcher instruments. No significant associations were found between scores and patient characteristics known to affect HRQoL. The EQ-5D-5L instrument found an improvement in HRQoL following treatment, with the StM and SM dimensions of the English language MINICHAL trending to support this (d = 0.32 and 0.02 respectively). CONCLUSIONS: The present study details the successful English translation and validation of the MINICHAL instrument for use in individuals with hypertension. The data reported also supports an improvement in HRQoL with rapid treatment of grade II-III hypertension, a strategy which has been recommended by contemporaneous European guidelines. Trial registration ISRCTN registry number: 57475376 (assigned 25/06/2015).

Enhanced on-chip frequency measurement using weak value amplification.

We present an integrated design to sensitively measure changes in optical frequency using weak value amplification with a multi-mode interferometer. The technique involves introducing a weak perturbation to the system and then post-selecting the data in such a way that the signal is amplified without amplifying the technical noise, as has previously been demonstrated in a free-space setup. We demonstrate the advantages of a Bragg grating with two band gaps for obtaining simultaneous, stable high transmission and high dispersion. The device is more robust and easily scalable than the free-space implementation, and provides amplified sensitivity compared to other methods of measuring changes in optical frequency on a chip, such as an integrated Mach-Zehnder interferometer.

Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives.

Dipolar aprotic and ethereal solvents comprise just over 40% of all organic solvents utilized in synthetic organic, medicinal, and process chemistry. Unfortunately, many of the common "go-to" solvents are considered to be "less-preferable" for a number of environmental, health, and safety (EHS) reasons such as toxicity, mutagenicity, carcinogenicity, or for practical handling reasons such as flammability and volatility. Recent legislative changes have initiated the implementation of restrictions on the use of many of the commonly employed dipolar aprotic solvents such as dimethylformamide (DMF) and N-methyl-2-pyrrolidinone (NMP), and for ethers such as 1,4-dioxane. Thus, with growing legislative, EHS, and societal pressures, the need to identify and implement the use of alternative solvents that are greener, safer, and more sustainable has never been greater. Within this review, the ubiquitous nature of dipolar aprotic and ethereal solvents is discussed with respect to the physicochemical properties that have made them so appealing to synthetic chemists. An overview of the current legislative restrictions being imposed on the use of dipolar aprotic and ethereal solvents is discussed. A variety of alternative, safer, and more sustainable solvents that have garnered attention over the past decade are then examined, and case studies and examples where less-preferable solvents have been successfully replaced with a safer and more sustainable alternative are highlighted. Finally, a general overview and guidance for solvent selection and replacement are included in the Supporting Information of this review.

Infective endocarditis following heart transplantation: A systematic review.

PURPOSE: Infective endocarditis (IE) is a rare but potentially fatal complication following heart transplantation (HTx). There is a lack of literature regarding the patterns and clinical course of IE development following HTx. We sought to pool the existing data in regards to defining characteristics, management options, and outcomes of IE following HTx. METHODS: An electronic search of Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, Ovid Medline, and the Scopus databases were performed to identify all articles in the English literature that report IE following HTx in adult patients. Patient-level data were extracted and analyzed. RESULTS: Systematic search yielded 57 patients from 32 articles. Median patient age was 52 [IQR 43, 59] and 75% of patients (43/57) were male. Median time to IE presentation post-HTx was 8.4 [IQR 3.0, 35.8] months. IE of the mitral valve was observed in 36.8% (21/57) of patients, followed by mural IE in 24.6% (14/57), and tricuspid valve IE in 21.1% (12/57). The most common organisms were Staphylococcus aureus in 26.3% (15/57), Aspergillus fumigatus in 19.3% (11/57), Enterococcus faecalis in 12.3% (7/57), and an undetermined or unspecified organism in 14.0% (8/57) patients. Overall case fatality was 44.6% (25/56). Fungal IE was associated with a significantly higher case fatality 75.0% (9/12) than that of bacterial IE 36.1% (13/36) (p = 0.02). Surgical management of post-HTx IE was observed in 35.1% (20/57) of patients. This included valve surgery for 70.0% (14/20), including the mitral valve in 50.0% (7/14), aortic valve in 35.7% (5/14), and the tricuspid valve in 14.3% (2/14) of patients. CONCLUSION: In addition to bacterial organisms, fungi also represent a frequent cause of IE in post-HTx patients. Overall HTx patient survival in the setting of IE is poor and may be worse if caused by A. fumigatus.