Breakdown of Detailed Balance for Thermal Radiation by Synthetic Fields.

In recent times the possibility of nonreciprocity in heat transfer between two bodies has been extensively studied. In particular the role of strong magnetic fields has been investigated. A much simpler approach with considerable flexibility would be to consider heat transfer in synthetic electric and magnetic fields that are easily applied. We demonstrate the breakdown of detailed balance for the heat transfer function T(ω), i.e., the spectrum of heat transfer between two objects due to the presence of synthetic electric and magnetic fields. The spectral measurements carry much more physical information and are the reason for the quantum theory of radiation. We demonstrate explicitly the synthetic field induced nonreciprocity in the heat transfer transmission function between two graphene flakes and for the Casimir coupling between two objects. Unlike many other cases of heat transfer, the latter case has interesting features of the strong coupling. Further the presence of synthetic fields affects the mean occupation numbers of two membranes and we propose this system for the experimental verification of the breakdown of detailed balance.

Multiple myeloma screening within a fracture liaison service (FLS).

Multiple myeloma (MM) remains incurable. Although early diagnosis improves outcomes, it has been unclear which populations to target for screening with serum electrophoresis, serum free light chains and urine electrophoresis. Here, we assessed the value of MM screening in a Fracture Liaison Service, finding that 1 per 195 fragility fractures has undiagnosed MM, which can be expedited to Haematology Services. PURPOSE: A key role of the Fracture Liaison Service (FLS) is screening for secondary causes of osteoporosis. In 2019, the Royal Osteoporosis Society recommended that all patients attending FLS who are recommended anti-osteoporosis therapy have universal screening for myeloma based on serum electrophoresis, serum free light chains and urine electrophoresis. Here, we examined the impact of universal myeloma screening within an FLS. METHODS: We sampled all patients seen by the Oxfordshire FLS between January and April 2018. The completion rates and outcomes of screening were checked using the hospital and FLS databases. RESULTS: Of 950 patients identified by the FLS, 628 were eligible for MM screening; 473 (75%) of these were female, and the average age was 78.4 years. Overall, 584 had some form of myeloma screening, of which 577 (92%) had serum electrophoresis, 525 (84%) had serum free light chains and 407 (65%) had urine electrophoresis measured. A total of 327 (59%) patients had complete screening. Three patients (0.5%) had newly diagnosed myeloma and were urgently referred to Haematology Services. Furthermore, 46 (8%) patients had a detectable serum paraprotein with a likely diagnosis of monoclonal gammopathy of uncertain significance (MGUS) and referred for community annual surveillance according to local guidelines. CONCLUSION: Addition of universal myeloma screening to laboratory testing identified myeloma in 1 per 195 patients, and its precursor state MGUS in 1 per 13 patients, which may have otherwise been missed. Further analysis with long-term follow-up is needed to clearly define the value of diagnosing MGUS within the FLS setting and establish the benefits vs. costs and methods to improve screening completion rates.

Enhanced Sensing of Weak Anharmonicities through Coherences in Dissipatively Coupled Anti-PT Symmetric Systems.

In the last few years, the great utility of exceptional points in sensing linear perturbations has been recognized. However, physical systems are inherently anharmonic and macroscopic physics is most accurately described by nonlinear models. Considering the multitude of semiclassical and quantum effects ensuing from nonlinear interactions, the sensing of anharmonicities is a prerequisite to the primed control of these effects. Here, we propose an expedient sensing scheme relevant to dissipatively coupled anti parity-time (anti-PT) symmetric systems and customized for the fine-grained estimation of anharmonic perturbations. The sensitivity to anharmonicities is derived from the coherence between two modes induced by a common vacuum. Owing to this coherence, the linear response acquires a pole on the real axis. We demonstrate how this singularity can be exploited for the enhanced sensing of very weak anhamonicities at low pumping rates. Our results are applicable to a wide class of systems, and we specifically illustrate the remarkable sensing capabilities in the context of a weakly anharmonic yttrium iron garnet sphere interacting with a cavity via a tapered fiber waveguide. A small change in the anharmonicity leads to a substantial change in the induced spin current.

Long-Time Memory and Ternary Logic Gate Using a Multistable Cavity Magnonic System.

Multistability is an extraordinary nonlinear property of dynamical systems and can be explored to implement memory and switches. Here we experimentally realize the tristability in a three-mode cavity magnonic system with Kerr nonlinearity. The three stable states in the tristable region correspond to the stable solutions of the frequency shift of the cavity magnon polariton under specific driving conditions. We find that the system staying in which stable state depends on the history experienced by the system, and this state can be harnessed to store the history information. In our experiment, the memory time can reach as long as 5.11 s. Moreover, we demonstrate the ternary logic gate with good on-off characteristics using this multistable hybrid system. Our new findings pave a way towards cavity magnonics-based information storage and processing.

Role of postoperative intact serum PTH as an early predictor of severe post-thyroidectomy hypocalcemia: a prospective study.

BACKGROUND: Post thyroidectomy hypocalcemia is a major sequel of thyroidectomy and continues to trouble the endocrinologists and the endocrine surgeons as there is no ideal predictive marker of hypocalcemia which has the potential to develop into a life-threatening complication. The role of early serum intact parathormone (iPTH) to predict post thyroidectomy hypocalcemia is becoming useful but the literature is still unclear regarding the optimal time of testing and the optimal cut-off value of serum iPTH. PATIENTS AND METHODS: This is a prospective cohort study of 111 patients who underwent total thyroidectomy in a tertiary care endocrine surgery referral unit. Serum iPTH was measured after 20 min and 4 h of surgery. Receiver-Operator characteristic Curve (ROC) was used to find out of the best cut-off value of S. iPTH 20 min and 4 h after surgery in predicting hypocalcemia. RESULTS: Hypocalcemia was noted in 60 (54%) out of 111 subjects who underwent total thyroidectomy. The best cut-off values of Serum iPTH to predict hypocalcemia was found to be 4.28 pmol/l at 20 min post total thyroidectomy with a sensitivity and specificity of 81.7% and 51%, respectively. In addition, patients with malignancy or central lymph nodal dissection were significantly over-represented in the hypocalcemia group with serum iPTH above the threshold level of 4.28 pmol/l. Below the cut off level, parenteral calcium supplementation was required in 23% (17/74) subjects while the rate was only 5.4% (2/37) patients when serum iPTH was above the cut-off level. CONCLUSIONS: The decline of serum iPTH below a specific level after surgery has predictive value together with other factors strictly related to patient, the thyroid disease itself and surgery. The risk of development of hypocalcemia and consequent need for calcium supplementation should be evaluated by clinical assessment along with serum PTH measurement.

Squeezed Light Induced Symmetry Breaking Superradiant Phase Transition.

We theoretically investigate the quantum phase transition in the collective systems of qubits in a high quality cavity, where the cavity field is squeezed via the optical parametric amplification process. We show that the squeezed light induced symmetry breaking can result in quantum phase transition without the ultrastrong coupling requirement. Using the standard mean field theory, we derive the condition of the quantum phase transition. Surprisingly, we show that there exists a tricritical point where the first- and second-order phase transitions meet. With specific atom-cavity coupling strengths, both the first- and second-order phase transition can be controlled by the nonlinear gain coefficient, which is sensitive to the pump field. These features also lead to an optical switching from the normal phase to the superradiant phase by just increasing the pump field intensity. The signature of these phase transitions can be observed by detecting the phase space Wigner function distribution with different profiles controlled by the squeezed light intensity. Such superradiant phase transition can be implemented in various quantum systems, including atoms, quantum dots, and ions in optical cavities as well as the circuit quantum electrodynamics system.

Detector-Agnostic Phase-Space Distributions.

The representation of quantum states via phase-space functions constitutes an intuitive technique to characterize light. However, the reconstruction of such distributions is challenging as it demands specific types of detectors and detailed models thereof to account for their particular properties and imperfections. To overcome these obstacles, we derive and implement a measurement scheme that enables a reconstruction of phase-space distributions for arbitrary states whose functionality does not depend on the knowledge of the detectors, thus defining the notion of detector-agnostic phase-space distributions. Our theory presents a generalization of well-known phase-space quasiprobability distributions, such as the Wigner function. We implement our measurement protocol, using state-of-the-art transition-edge sensors without performing a detector characterization. Based on our approach, we reveal the characteristic features of heralded single- and two-photon states in phase space and certify their nonclassicality with high statistical significance.

Sensing single atoms in a cavity using a broadband squeezed light.

We investigate a single atom cavity-QED system directly driven by a broadband squeezed light. We demonstrate how the squeezed radiation can be used to sense the presence of a single atom in a cavity. This happens by transferring one of the photons from the field in a state with an even number of photons to the atom and thereby populating an odd number of Fock states. Specifically, the presence of the atom is sensed by remarkable changing in the presence of one photon and the loss of squeezing of the cavity field. A complete study of quantum fluctuations and the excitation of multiphoton transitions is given.

Beam Focusing and Reduction of Quantum Uncertainty in Width at the Few-Photon Level via Multi-Spatial-Mode Squeezing.

We show for the first time that it is possible to realize laser beam focusing at the few-photon level in the four-wave-mixing process, and at the same time reduce the quantum uncertainty in width. The reduction in quantum uncertainty results directly from the strong suppression of local intensity fluctuations. This surprising effect of simultaneous focusing and reduction of width uncertainty is enabled by multi-spatial-mode (MSM) squeezing, and is not possible via any classical optical approach or single-spatial-mode squeezing. Our results open promising possibilities for quantum-enhanced imaging and metrology; as an example, the limit on the measurement of very small beam displacement can be enhanced within feasible experimental parameters because of beam focusing and the noiseless amplification in the MSM squeezing process.

Global Disparities in Breast Cancer Genetics Testing, Counselling and Management.

Hereditary breast cancers, mainly due to BRCA1 and BRCA2 mutations, account for only 5-10% of this disease. The threshold for genetic testing is a 10% likelihood of detecting a mutation, as determined by validated models such as BOADICEA and Manchester Scoring System. A 90-95% reduction in breast cancer risk can be achieved with bilateral risk-reducing mastectomy in unaffected BRCA mutation carriers. In patients with BRCA-associated breast cancer, there is a 40% risk of contralateral breast cancer and hence risk-reducing contralateral mastectomy is recommended, which can be performed simultaneously with surgery for unilateral breast cancer. Other options for risk management include surveillance by mammogram and breast magnetic resonance imaging, and chemoprevention with hormonal agents. With the advent of next-generation sequencing and development of multigene panel testing, the cost and time taken for genetic testing have reduced, making it possible for treatment-focused genetic testing. There are also drugs such as the PARP inhibitors that specifically target the BRCA mutation. Risk management multidisciplinary clinics are designed to quantify risk, and offer advice on preventative strategies. However, such services are only possible in high-income settings. In low-resource settings, the prohibitive cost of testing and the lack of genetic counsellors are major barriers to setting up a breast cancer genetics service. Family history is often not well documented because of the stigma associated with cancer. Breast cancer genetics services remain an unmet need in low- and middle-income countries, where the priority is to optimise access to quality treatment.

Enhancement of electromagnetically induced transparency in metamaterials using long range coupling mediated by a hyperbolic material.

Near-field coupling is a fundamental physical effect, which plays an important role in the establishment of classical analog of electromagnetically induced transparency (EIT). However, in a normal environment the coupling length between the bright and dark artificial atoms is very short and far less than one wavelength, owing to the exponentially decaying property of near fields. In this work, we report the realization of a long range EIT, by using a hyperbolic metamaterial (HMM) which can convert the near fields into high-k propagating waves to overcome the problem of weak coupling at long distance. Both simulation and experiment show that the coupling length can be enhanced by nearly two orders of magnitude with the aid of a HMM. This long range EIT might be very useful in a variety of applications including sensors, detectors, switch, long-range energy transfer, etc.

Magnon-Photon-Phonon Entanglement in Cavity Magnomechanics.

We show how to generate tripartite entanglement in a cavity magnomechanical system which consists of magnons, cavity microwave photons, and phonons. The magnons are embodied by a collective motion of a large number of spins in a macroscopic ferrimagnet, and are driven directly by an electromagnetic field. The cavity photons and magnons are coupled via magnetic dipole interaction, and the magnons and phonons are coupled via magnetostrictive (radiation pressurelike) interaction. We show optimal parameter regimes for achieving the tripartite entanglement where magnons, cavity photons, and phonons are entangled with each other, and we further prove that the steady state of the system is a genuinely tripartite entangled state. The entanglement is robust against temperature. Our results indicate that cavity magnomechanical systems could provide a promising platform for the study of macroscopic quantum phenomena.

Detector-Independent Verification of Quantum Light.

We introduce a method for the verification of nonclassical light which is independent of the complex interaction between the generated light and the material of the detectors. This is accomplished by means of a multiplexing arrangement. Its theoretical description yields that the coincidence statistics of this measurement layout is a mixture of multinomial distributions for any classical light field and any type of detector. This allows us to formulate bounds on the statistical properties of classical states. We apply our directly accessible method to heralded multiphoton states which are detected with a single multiplexing step only and two detectors, which are in our work superconducting transition-edge sensors. The nonclassicality of the generated light is verified and characterized through the violation of the classical bounds without the need for characterizing the used detectors.

Effectiveness of a community paramedic-led health assessment and education initiative in a seniors' residence building: the Community Health Assessment Program through Emergency Medical Services (CHAP-EMS).

BACKGROUND: Seniors living in subsidized housing have lower income, poorer health, and increased risk for cardiometabolic diseases and falls. Seniors also account for more than one third of calls to Emergency Medical Services (EMS). This study examines the effectiveness of the Community Health Assessment Program through EMS (CHAP-EMS) in reducing blood pressure, diabetes risk, and EMS calls. METHODS: Paramedics on modified duty (e.g. injured) conducted weekly, one-on-one drop-in sessions in a common area of one subsidized senior's apartment building in Hamilton, Ontario. Paramedics assessed cardiovascular, diabetes, and fall risk, provided health education, referred participants to local resources, and encouraged participants to return to CHAP-EMS for follow-up. Reports were faxed to the family physician regularly. Blood pressure was collected throughout the one year intervention, while diabetes risk was assessed at baseline and after 6-12 months. EMS call volumes were collected from the Hamilton Paramedic Service for two years pre-intervention and one year during the intervention. RESULTS: There were 79 participants (mean age = 72.2 years) and 1,365 participant visits to CHAP-EMS. The majority were female (68%), high school educated or less (53%), had a family doctor (90%), history of hypertension (58%), high waist circumference (64%), high body mass index (61%), and high stress (53%). Many had low physical activity (42%), high fat intake (33%), low fruit/vegetable intake (30%), and were current smokers (29%). At baseline, 42% of participants had elevated blood pressure. Systolic blood pressure decreased significantly by the participant's 3rd visit to CHAP-EMS and diastolic by the 5th visit (p < .05). At baseline, 19% of participants had diabetes; 67% of those undiagnosed had a moderate or high risk based on the Canadian Diabetes Risk (CANRISK) assessment. 15% of participants dropped one CANRISK category (e.g. high to moderate) during the intervention. EMS call volume decreased 25% during the intervention compared to the previous two years. CONCLUSIONS: CHAP-EMS was associated with a reduction in emergency calls and participant blood pressure and a tendency towards lowered diabetes risk after one year of implementation within a low income subsidized housing building with a history of high EMS calls. TRIAL REGISTRATION: Retrospectively registered on May 12th 2016 with clinicaltrials.gov: NCT02772263.

Time-reversal-symmetric single-photon wave packets for free-space quantum communication.

Readout and retrieval processes are proposed for efficient, high-fidelity quantum state transfer between a matter qubit, encoded in the level structure of a single atom or ion, and a photonic qubit, encoded in a time-reversal-symmetric single-photon wave packet. They are based on controlling spontaneous photon emission and absorption of a matter qubit on demand in free space by stimulated Raman adiabatic passage. As these processes do not involve mode selection by high-finesse cavities or photon transport through optical fibers, they offer interesting perspectives as basic building blocks for free-space quantum-communication protocols.

Coherent perfect absorption of path entangled single photons.

We examine the question of coherent perfect absorption (CPA) of single photons, and more generally, of the quantum fields by a macroscopic medium. We show the CPA of path entangled single photons in a Fabry-Perot interferometer containing an absorptive medium. The frequency of perfect absorption can be controlled by changing the interferometer parameters like the reflectivity and the complex dielectric constant of the material. We exhibit similar results for path entangled photons in micro-ring resonators. For entangled fields like the ones produced by a down converter the CPA aspect is evident in phase sensitive detection schemes such as in measurements of the squeezing spectrum.

Two-photon quantum interference in plasmonics: theory and applications.

We report perfect two-photon quantum interference with near-unity visibility in a resonant tunneling plasmonic structure in folded Kretschmann geometry. This is despite absorption-induced loss of unitarity in plasmonic systems. The effect is traced to perfect destructive interference between the squares of amplitude reflection and transmission coefficients. We further highlight yet another remarkable potential of coincidence measurements as a probe with better resolution as compared to standard spectroscopic techniques. The finer features show up in both angle resolved and frequency resolved studies.

Directional superradiant emission from statistically independent incoherent nonclassical and classical sources.

Superradiance has been an outstanding problem in quantum optics since Dicke introduced the concept of enhanced directional spontaneous emission by an ensemble of identical two-level atoms. The effect is based on the correlated collective Dicke states which turn out to be highly entangled. Here we show that enhanced directional emission of spontaneous radiation can be produced also with statistically independent incoherent sources, via the measurement of higher-order correlation functions of the emitted radiation. Our analysis is applicable to a wide variety of quantum emitters, like trapped atoms, ions, quantum dots, or nitrogen-vacancy centers, and is also valid for incoherent classical emitters. This is experimentally confirmed with up to eight statistically independent thermal light sources. The arrangement to measure the higher-order correlation functions corresponds to a generalized Hanbury Brown-Twiss setup, demonstrating that the two phenomena, superradiance and the Hanbury Brown-Twiss effect, stem from the same interference phenomenon.

Competitive immunochromatographic assay for the detection of thiodiglycol sulfoxide, a degradation product of sulfur mustard.

An immunochromatographic assay (ICA) based on the competitive antigen-coated format using colloidal gold as the label was developed for the detection of thiodiglycol sulfoxide (TDGO), an important metabolite and degradation compound of sulphur mustard (SM). The ICA test strip consisted of a membrane with a detection zone, a sample pad and an absorbent pad. The membrane was separately coated with hapten-OVA conjugate (test line) and anti-rabbit mouse IgG (control line). The visual detection limit for TDGO by ICA detection was found to be 10 µg mL(-1). For validation, the ICA results obtained for spiked water samples were in good agreement with those obtained by indirect competitive inhibition enzyme-linked immunosorbent assay (ELISA) for TDGO. The assay time for detection was less than 10 min. The developed ICA has the potential to be a useful on-site screening tool for the retrospective detection of SM in environmental samples.