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Background: Acute ischemic stroke due to basilar artery occlusion (BAO) is associated with the highest mortality in patients with large vessel occlusion. This study aimed to identify modifiable risk factors of early mortality in patients with BAO. Methods and Results: This was a cohort study of consecutive patients with BAO admitted to 47 stroke centers in China between January 2014 and May 2019. The primary outcome was all-cause mortality within 7 days after hospitalization. Of 829 patients, 164 died (0–3 days: 115; 4–7 days: 49) within 7 days after hospitalization. Among pre- and periprocedural variables, higher admission National Institutes of Health Stroke Scale (NIHSS, adjusted OR, 1.06, 95% CI: 1.04–1.09; p < 0.001), lower admission posterior circulation-Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS, adjusted OR, 0.88, 95% CI: 0.79–0.98; p = 0.02), lower Basilar Artery on Computed Tomography Angiography score (BATMAN, adjusted OR, 0.84, 95% CI: 0.76–0.93; p = 0.001), and recanalization failure (adjusted OR, 2.99, 95% CI: 2.04–4.38; p < 0.001) were independently associated with a higher risk of early mortality. Herniation (adjusted OR, 2.84, 95% CI: 1.52–5.30; p = 0.001) is an independent postprocedural predictor of early mortality. In patients dying ≤3 days, higher NIHSS (p < 0.001), lower pc-ASPECTS (p = 0.01), lower BATMAN (p = 0.004), recanalization failure (p < 0.001), herniation (p = 0.001), gastrointestinal hemorrhage (p = 0.046), and absence of pneumonia (p < 0.001) were independent predictors of early mortality. Higher NIHSS (p = 0.01), recanalization failure (p < 0.001), and pneumonia (p = 0.03) were independently associated with early mortality between 4 and 7 days. Conclusions: Recanalization failure, herniation, gastrointestinal hemorrhage, and pneumonia are potentially modifiable risk factors for early mortality in basilar artery occlusion.

We report parametric gain by utilizing $ \chi^{(2)} $ non-linearities in a semiconductor Bragg Reflection Waveguide (BRW) waveguide chip. Under the two-mode degenerate type II phase matching, it can be shown that more than 18 dBs of parametric gain for both TE and TM modes is tenable in 100s of micrometers of device length. Polarization insensitive parametric gain can be attained within the 1550 nm region of the spectrum. These AlGaAs BRW waveguides exhibit sub-photon per pulse sensitivity. This is in sharp contrast to other types of parametric gain devices which utilize $ \chi^{(3)} $, where the pump wavelength is in the vicinity of the signal wavelength. This sensitivity, which reached 0.1~photon/pulse, can usher a new era for on-chip quantum information processing using compact, micrometer-scale devices., Comment: 9 pages, 9 figures

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening medical condition with a high mortality and disability rate. aSAH has an unclear pathogenesis, and limited treatment options are available. Here, we aimed to identify critical genes involved in aSAH pathogenesis using peripheral blood gene expression data of 43 patients with aSAH due to ruptured intracranial aneurysms and 18 controls with headache, downloaded from Gene Expression Omnibus. These data were used to construct a co-expression network using weighted gene co-expression network analysis (WGCNA). The biological functions of the hub genes were explored, and critical genes were selected by combining with differentially expressed genes analysis. Fourteen modules were identified by WGCNA. Among those modules, red, blue, brown and cyan modules were closely associated with aSAH. Moreover, 364 hub genes in the significant modules were found to play important roles in aSAH. Biological function analysis suggested that protein biosynthesis-related processes and inflammatory responses-related processes were involved in the pathology of aSAH pathology. Combined with differentially expressed genes analysis and validation in 35 clinical samples, seven gene (CD27, ANXA3, ACSL1, PGLYRP1, ALPL, ARG1, and TPST1) were identified as potential biomarkers for aSAH, and three genes (ANXA3, ALPL, and ARG1) were changed with disease development, that may provide new insights into potential molecular mechanisms for aSAH.

Background Abnormal hypoperfusion on the surgical side after carotid artery stenting is rare. Neurological deterioration caused by it is deceptive, which can easily lead to misdiagnosis. The mechanism of hypoperfusion has rarely been demonstrated. We present here a fully studied case with a high probability of intracerebral steal phenomenon. Case presentation A 68-year-old male with severe right internal carotid artery stenosis and left internal carotid artery occlusion underwent right stenosis stent implantation. Restlessness and left limb hemiplegia occurred within 24 h after the procedure, which was similar to hyperperfusion syndrome. However, postoperative computerized tomography perfusion (CTP) revealed abnormal hypoperfusion in the right hemisphere. Transcranial Doppler (TCD) also showed decreased flow velocity in the right middle cerebral artery, and increased flow velocity in the right anterior cerebral artery. We considered that intracerebral steal phenomenon might be the cause, then hypervolemic therapy was accepted and the symptoms completely resolved after 3 days. Conclusions Ipsilateral hypoperfusion is rarely seen after carotid artery stenting. Intracerebral steal phenomenon may be the underlying mechanism. CTP or TCD is helpful for the early detection of this adverse event.

We have demonstrated a monolithic semiconductor passively mode-locked Bragg waveguide laser (PMBRL) based on a two quantum well active region. The lasers showed a threshold current of ~33 mA at a saturable absorber reverse bias of 0 V in continuous wave operation (CW), with emission wavelength of ~785 nm. A systematic study of a two section PMBRLs showed that these devices can generate pulse widths down to 211 fs at a 64 GHz repetition rate with a time-bandwidth product of 0.32. This range of pulse widths sets a new record for quantum well based devices.

The first χ2-based AlGaAs pulsed PSA with substantial confinement. This PSA achieves on chip in-phase gain of 30 dB, a sensitivity of 0.005 photons per pulse, and approaches the genuine quantum noise figure (NF) of 0 dB in near single mode operation for all degrees of freedom.

Phase sensitive amplifiers (PSAs) have the potential to empower substantial advances in emerging generations of optical communication systems as well as classical and quantum on-chip signal processing. While second order nonlinearity ( χ 2 ) is stronger than third order nonlinearity ( χ 3 ), it is seldom utilized in semiconductors to realize PSAs owing to the challenges of effectively phase matching the interacting waves as well as countering the two-photon absorption of the pump. In this work, we demonstrate the successful design, fabrication, and characterization of, to our knowledge, the first χ 2 -based semiconductor PSA using an efficient phase matching approach and a pulsed pump, in an AlGaAs Bragg reflection waveguide. The reported AlGaAs PSA achieves on-chip in-phase gain approaching 30 dB, with a sensitivity of 0.005 photons per pulse. Its performance also approaches the theoretical minimal noise figure of 0 dB. With such performance metrics and its capability to operate in the single mode regime, this PSA could usher in a new era of on-chip quantum circuits.

Introduction: Stroke etiology may affect the prognosis of acute basilar artery occlusion (BAO). This study aimed to estimate the efficacy and safety of endovascular treatment (EVT) in BAO strokes due to the underlying stroke etiologies of large artery atherosclerosis (LAA) and cardioembolism (CE). Patients and methods: Patients with LAA and CE subtypes from the registry EVT for Acute Basilar Artery Occlusion Study (BASILAR) were selected for this analysis. We estimated the EVT treatment effect relative to standard medical treatment (SMT) in these patients by using a propensity score approach with inverse probability of treatment weighted estimation. Outcomes included 90-day favorable functional outcomes (modified Rankin scale (mRS) 0–3), functional independence (mRS 0–2), all-cause mortality, and symptomatic intracranial hemorrhage (sICH). Results: A total of 744 patients were included in the final analysis. After weighting with inverse probability of treatment estimation, the patients who, based on their characteristics, were treated with EVT rather than SMT, demonstrated higher rates of favorable functional outcomes in both the LAA (29.2% vs 11.7%, adjusted OR with 95% CI: 4.34 [2.15–8.78], p Conclusions: In acute BAO strokes, both LAA and CE patients who, based on their characteristics, were treated with EVT rather than SMT, demonstrated better outcomes. Among EVT patients, LAA and CE subtypes displayed important baseline and treatment differences, and LAA patients were less likely to achieve functional independence at 3 months, but mortality and sICH were similar between LAA or CE subtypes. These results need to be confirmed in future clinical trials.

OBJECTIVE Authors of this study aimed to investigate the efficacy and safety of endovascular treatment (EVT) versus standard medical treatment (SMT) alone in patients with acute basilar artery occlusion (BAO) and moderate deficit (National Institutes of Health Stroke Scale [NIHSS] score 10–19). METHODS Patients with moderate deficit caused by acute BAO in the period from January 2014 to May 2019 were included in the study. The patients were divided into groups based on treatment: EVT plus SMT group or SMT-alone group. The primary outcome was favorable functional outcome (modified Rankin Scale score 0–3) at 90 days, and safety outcomes were symptomatic intracerebral hemorrhage (sICH) and mortality at 90 days. RESULTS A total of 173 patients had moderate deficits, 128 of whom had been treated with EVT and 45 with SMT alone. EVT was associated with a significant higher proportion of 90-day favorable outcomes compared with SMT (adjusted odds ratio [aOR] 4.09, 95% CI 1.39–12.04, p = 0.011). Younger age (aOR 0.96, 95% CI 0.92–0.99, p = 0.017), absence of diabetes mellitus (aOR 0.35, 95% CI 0.12–0.99, p = 0.048), higher baseline posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS; aOR 1.48, 95% CI 1.07–2.05, p = 0.018), and modified Thrombolysis in Cerebral Infarction (mTICI) score of 2b–3 (aOR 15.15, 95% CI 3.07–74.72, p = 0.001) were independent factors for a favorable outcome in the EVT group. Rates of mortality and sICH were comparable in the EVT and SMT groups. CONCLUSIONS EVT leads to improved outcomes compared to those with SMT alone. Younger age, absence of diabetes mellitus, higher baseline pc-ASPECTSs, and mTICI score of 2b–3 were associated with better functional outcome in the EVT group.

We demonstrated the first, 5th order ~790-805 nm edge-emitting semiconductor distributed feedback Bragg reflection waveguide laser with a side-mode suppression ratio of 49 dB and a corresponding linewidth of 207 kHz.

This Letter presents, to the best of our knowledge, the first report of a narrow-linewidth ∼ 790 − 800 n m edge-emitting semiconductor distributed feedback Bragg reflection waveguide diode laser ( D F B 2 R L ). The D F B 2 R L s were fabricated using a ridge waveguide structure with 5th order, surface-etched grating forming the wavelength selective element. Unbonded devices with a 500 µm cavity length exhibited continuous wave threshold currents in the region of 25 mA with an output power of 2.5 mW per (uncoated) facet at 100 mA drive current. The devices operated in a single longitudinal mode, with side-mode suppression ratio (SMSR) as high as 49 dB and linewidths as low as 207 kHz. Devices maintained single mode operation with high SMSR over a 9 nm wavelength range as the temperature was swept from 15°C to 50°C.

The expansion of optical network traffic demands the implementation of all-optical signal processing functions such as switching and modulation within the network nodes to scale data speeds and curb power consumption. Toward this end, we experimentally demonstrate ultracompact all-optical modulators based on vanadium dioxide that can be operated by broadband control (800–1000 nm) and signal (1500–1600 nm) wavelengths and are simultaneously switched by pulse energies as low as 6.4 pJ. The devices are integrated on-chip and enable planar propagation of both control and signal light beams. For a 4 μm length modulator, the extinction ratio is 1.68 dB/μm and the insertion loss is 0.98 dB/μm at λ = 1550 nm. To our knowledge, these characteristics together have not been demonstrated previously in a single device. Furthermore, the extinction ratio, switching energy, and switching efficiency have been observed to depend on the modulator length in subtle ways, which is due to the finite distance required for the el...

Tirofiban is a highly selective nonpeptide antagonist of glycoprotein IIb/IIIa receptor, which reversibly inhibits platelet aggregation. It remains uncertain whether intravenous tirofiban is effective to improve functional outcomes for patients with large vessel occlusion ischemic stroke undergoing endovascular thrombectomy.To assess the efficacy and adverse events of intravenous tirofiban before endovascular thrombectomy for acute ischemic stroke secondary to large vessel occlusion.This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 55 hospitals in China, enrolling 948 patients with stroke and proximal intracranial large vessel occlusion presenting within 24 hours of time last known well. Recruitment took place between October 10, 2018, and October 31, 2021, with final follow-up on January 15, 2022.Participants received intravenous tirofiban (n = 463) or placebo (n = 485) prior to endovascular thrombectomy.The primary outcome was disability level at 90 days as measured by overall distribution of the modified Rankin Scale scores from 0 (no symptoms) to 6 (death). The primary safety outcome was the incidence of symptomatic intracranial hemorrhage within 48 hours.Among 948 patients randomized (mean age, 67 years; 391 [41.2%] women), 948 (100%) completed the trial. The median (IQR) 90-day modified Rankin Scale score in the tirofiban group vs placebo group was 3 (1-4) vs 3 (1-4). The adjusted common odds ratio for a lower level of disability with tirofiban vs placebo was 1.08 (95% CI, 0.86-1.36). Incidence of symptomatic intracranial hemorrhage was 9.7% in the tirofiban group vs 6.4% in the placebo group (difference, 3.3% [95% CI, -0.2% to 6.8%]).Among patients with large vessel occlusion acute ischemic stroke undergoing endovascular thrombectomy, treatment with intravenous tirofiban, compared with placebo, before endovascular therapy resulted in no significant difference in disability severity at 90 days. The findings do not support use of intravenous tirofiban before endovascular thrombectomy for acute ischemic stroke.Chinese Clinical Trial Registry Identifier: ChiCTR-IOR-17014167.

We demonstrate a passively mode-locked semiconductor Bragg waveguide laser which exhibit pulse widths down to 211 fs at 64 GHz. The dispersion of Bragg waveguides enables this new record, especially for emission around 785 nm.

All-optical, non-resonant, in-plane Si3N4/VO2 modulators offering 6.4 pJ switching energy, 1.68 dB/pm extinction ratio, and 4 pm length are demonstrated. This is obtained with broadband control (800-1000 nm) and signal (1500-1600 nm) wavelengths.

We demonstrate and analyze how deploying non-classical intensity correlations obtained from a monolithic semiconductor quantum photon source can enhance classical target detection systems. This is demonstrated by examining the advantages offered by the utilization of the non-classical correlations in a correlation based target detection protocol. We experimentally demonstrate that under the same condition, the target contrast obtained from the protocol when non-classical correlations are utilized exhibits an improvement of up to 17.79 dB over the best classical intensity correlation-based target detection protocol [1] , under 29.69dB channel loss and excess noise 13.40dB stronger than the probe signal. We also assessed how the strong frequency correlations within the non-classical photon pairs can be used to further enhance this protocol.

A meshless radial basis function (RBF) collocation method based on the Eringen nonlocal elasticity theory is developed to calculate the band structures of ternary and quaternary nanoscale multi-layered phononic crystals (PNCs) with functionally graded (FG) interlayers. Detailed calculations are performed for anti-plane transverse waves propagating in such PNCs. The influences of FG and homogeneous interlayers, component number, nonlocal interface imperfections and nanoscale size on cut-off frequency and band structures are investigated in detail. Numerical results show that these factors have significant effects on band structures at the macroscopic and microscopic scales.

The localization characteristics of the in-plane elastic waves in locally resonant aperiodic phononic crystals are examined in this study. In particular, the phononic crystals generated according to the Thue–Morse, Rudin–Shapiro and Period-Doubling sequences are theoretically investigated by using the extended transfer matrix method. For comparison, the binary and ternary locally resonant systems are considered, and their band structures are characterized by using the localization factors. Moreover, the influences of structural arrangement, material combination, incidence angle, number of components, length ratio, and random disorder on the band structures are also discussed. Some novel and interesting phenomena are observed and discussed.

In this paper, the radial basis function (RBF) collocation method based on the nonlocal Eringen piezoelectricity theory is developed to compute the band structures of nanoscale multilayered piezoelectric phononic crystals taking account of nonlocal interface effects. Detailed calculations are performed for anti-plane transverse waves propagating obliquely or vertically in the system. The correctness of the present method is verified by comparing the numerical results with those obtained by applying the transfer matrix method in the case of nonlocal perfect interfaces. The effects of nonlocal interface imperfections are considered by comparing with the nonlocal perfect interfaces. In addition, the influences of the piezoelectric constant, the nanoscale size, the impedance ratio and the incidence angle on the cut-off frequency and band structures are investigated and discussed in detail. Numerical results show that the nonlocal interface discontinuity has more obvious effect on the low-frequency band structures at the microscopic scale than at the macroscopic scale. Furthermore, at the macroscopic scale, the nonlocal interface imperfection has an obvious effect on the high frequency waves, but the effect on the low frequency waves is not obvious, and the nonlocal interface imperfection has no effect on the cut-off frequency at the microscopic scale.

A radial basis function collocation method based on the nonlocal elastic continuum theory is developed to compute the band structures of nanoscale multilayered phononic crystals. The effects of nonlocal imperfect interfaces on band structures of transverse waves propagating obliquely or vertically in the system are studied. The correctness of the present method is verified by comparing the numerical results with those obtained by applying the transfer matrix method in the case of nonlocal perfect interface. Furthermore, the influences of the nanoscale size, the impedance ratio and the incident angle on the cut-off frequency and band structures are investigated and discussed in detail. Numerical results show that the nonlocal interface imperfections have significant effects on the band structures in the macroscopic and microscopic scale.

The mesh-free radial basis function (RBF) collocation method is explored to calculate band structures of periodic composite structures. The inverse multi-quadric (MQ), Gaussian, and MQ RBFs are used to test the stability of the RBF collocation method in periodic structures. Much useful information is obtained. Due to the merits of the RBF collocation method, the general form in this paper can easily be applied in the high dimensional problems analysis. The stability is fully discussed with different RBFs. The choice of the shape parameter and the effects of the knot number are presented.

Background: The optimal treatment strategy for residual stenosis in patients with acute intracranial atherosclerotic stenosis related occlusion (ICAS-O) after endovascular treatment (EVT) is unknown. This study aims to evaluate the efficacy and safety of low-dose tirofiban in patients with residual stenosis after EVT due to acute ICAS-O. Methods: Retrospective analysis of prospectively enrolled consecutive patients with residual stenosis after EVT due to acute ICAS-O from March 2015 to May 2019. Patients were divided into EVT alone group or EVT plus tirofiban group. The primary endpoint was the favorable functional outcome (defined as modified Rankin scale score of 0-2) at 90 days. The secondary endpoints were the proportions of reocclusion of recanalized arteries within 72 hours after EVT, symptomatic intracranial hemorrhage (sICH), any ICH, and mortality at 90 days. Logistic regression for predictors of reocclusion and functional outcomes were performed. Results: A total of 98 patients, 50 treated with tirofiban and 48 without tirofiban, were enrolled in this study. Compared with patients in EVT alone group, patients in EVT plus tirofiban group had higher favorable functional outcome rate, lower mortality, and a lower reocclusion rate (56.3% versus 30.4%; P = .014, 8.3% versus 28.3%; P = .016, and 10.4% versus 32.6%; P = .011, respectively). The rates of any ICH and sICH were similar between the 2 groups. The use of tirofiban was associated with the favorable functional outcome (odds ratio [OR], 3.417; 95% confidence interval [CI], 1.149-10.163; P = .027) and lower reocclusion rate (OR, 0.145; 95% CI, 0.038-0.546; P = .004) on multivariate logistic regression analysis. Conclusions: In patients with residual stenosis after EVT due to acute ICAS-O, a low-dose of tirofiban is associated with favorable functional outcome and reduced incidence of reocclusion without increasing any ICH and sICH.

Background and aims: Recently, several clinical trials have shown that increased glycated hemoglobin (HbA1c) level is correlated with poor clinical outcomes in ischemic stroke patients after thrombolysis and possibly after mechanical thrombectomy. However, the effect of HbA1c on posterior circulation large vessel occlusion (PCLVO) patients treated with endovascular thrombectomy (EVT) remains unclear. This multicenter study assessed the association between the HbA1c levels and clinical outcomes in patients with PCLVO after EVT. Methods: We studied 385 PCLVO ischemic stroke patients included in the EVT for acute basilar artery occlusion study (BASILAR). Patients were divided into a high HbA1c level group (HbA1c >6.5%) and a low HbA1c level group (HbA1c ⩽6.5%). The efficacy outcome was a 90-day favorable functional outcome (modified Rankin Scale 0–3). The safety outcomes included symptomatic intracerebral hemorrhage and mortality at 90 days after EVT. Results: The frequency of a favorable outcome in patients with an HbA1c ⩽6.5% was significantly higher than that in the HbA1c >6.5% group (41.2% versus 26.2%, p = 0.001). In multivariate analysis with adjusted confounders, high HbA1c levels and favorable outcomes were significantly negatively correlated. There was also a significant association between high HbA1c levels and mortality after 3 months. The negative effects of high HbA1c levels on functional status after 3 months were exacerbated in patients aged ⩾65 years. Conclusion: Our multicenter study suggests that a higher serum HbA1c level (HbA1c >6.5%) is an independent predictor of a 90-day poor outcome and mortality in patients with PCLVO after EVT, particularly in those aged ⩾65 years. Clinical Trial Registry identifier: ChiCTR1800014759.

The interaction of anti-plane elastic SH waves with a periodic array of interface cracks in a multi-layered periodic medium is analyzed in this paper. A perfect periodic structure without interface cracks is first studied and the transmission displacement coefficient is obtained based on the transfer matrix method in conjunction with the Bloch-Floquet theorem. This is then generalized to a single and periodic distribution of cracks at the center interface and the result is compared with that of perfect periodic cases without interface cracks. The dependence of the transmission displacement coefficient on the frequency of the incident wave, the influences of material combination, crack configuration and incident angle are discussed in detail. Compared with the corresponding perfect periodic structure without interface cracks, a new phenomenon is found in the periodic layered system with a single and periodic array of interface cracks.

The wave localization properties in locally resonant ternary phononic aperiodic crystals based on Thue-Morse and Rudin-Shapiro sequences, are theoretically investigated by the transfer matrix method. The various factors affecting localization characteristics are discussed. Numerical results show that the effect of material properties and the geometric structure parameters on the number and size of band gaps is obvious. Moreover, compared with the corresponding binary aperiodic structures without local resonances, the localization factors become larger in the locally resonant ternary structures. And wider and lower-frequency band gaps and localized resonant flat bands appear in the locally resonant aperiodic system. Compared with the locally resonant Thue-Morse system, the localization factor becomes larger and the band splitting phenomenon is less obvious in the locally resonant Rudin-Shapiro system, which is just the opposite to that in the aperiodic system without local resonance. This study is useful in filter, waveguide, and so on.

Quantum correlations are critical to our understanding of nature, with far-reaching technological and fundamental impact. These often manifest as violations of Bell's inequalities, bounds derived from the assumptions of locality and realism, concepts integral to classical physics. Many tests of Bell's inequalities have studied pairs of correlated particles; however, the immense interest in multi-particle quantum correlations is driving the experimental frontier to test systems beyond just pairs. All experimental violations of Bell's inequalities to date require supplementary assumptions, opening the results to one or more loopholes, the closing of which is one of the most important challenges in quantum science. Individual loopholes have been closed in experiments with pairs of particles and a very recent result closed the detection loophole in a six ion experiment. No experiment thus far has closed the locality loopholes with three or more particles. Here, we distribute three-photon Greenberger-Horne-Zeilinger entangled states using optical fibre and free-space links to independent measurement stations. The measured correlations constitute a test of Mermin's inequality while closing both the locality and related freedom-of-choice loopholes due to our experimental configuration and timing. We measured a Mermin parameter of 2.77 +/- 0.08, violating the inequality bound of 2 by over 9 standard deviations, with minimum tolerances for the locality and freedom-of-choice loopholes of 264 +/- 28 ns and 304 +/- 25 ns, respectively. These results represent a significant advance towards definitive tests of the foundations of quantum mechanics and practical multi-party quantum communications protocols., 13 pages, 8 figures

The band structures and localization properties of in-plane elastic waves with coupling of longitudinal and transverse modes oblique propagating in aperiodic phononic crystals based on Thue–Morse and Rudin–Shapiro sequences are studied. Using transfer matrix method, the concept of the localization factor is introduced and the correctness is testified through the Rytov dispersion relation. For comparison, the perfect periodic structure and the quasi-periodic Fibonacci system are also considered. In addition, the influences of the random disorder, local resonance, translational and/or mirror symmetries on the band structures of the aperiodic phononic crystals are analyzed in this paper.

The band structures of in-plane elastic waves propagating in two-dimensional phononic crystals with one-dimensional random disorder and aperiodicity are analyzed in this paper. The localization of wave propagation is discussed by introducing the concept of the localization factor, which is calculated by the plane-wave-based transfer-matrix method. By treating the random disorder and aperiodicity as the deviation from the periodicity in a special way, three kinds of aperiodic phononic crystals that have normally distributed random disorder, Thue–Morse and Rudin–Shapiro sequence in one direction and translational symmetry in the other direction are considered and the band structures are characterized using localization factors. Besides, as a special case, we analyze the band gap properties of a periodic planar layered composite containing a periodic array of square inclusions. The transmission coefficients based on eigen-mode matching theory are also calculated and the results show the same behaviors as the localization factor does. In the case of random disorders, the localization degree of the normally distributed random disorder is larger than that of the uniformly distributed random disorder although the eigenstates are both localized no matter what types of random disorders, whereas, for the case of Thue–Morse and Rudin–Shapiro structures, the band structures of Thue–Morse sequence exhibit similarities with the quasi-periodic (Fibonacci) sequence not present in the results of the Rudin–Shapiro sequence.

We report our experimental investigations on the radio frequency (RF) and microwave nonlinear behavior of the NbN nanowire meanderline. We construct a lumped element model of the NbN nanowire meanderline, which consists of a kinetic inductance, a normal resistance, and a parasitic capacitance that is a load of a transmission line. Two complementary measurements, which are based on the one-port scattering (S)-parameter technique, are used to explore the nonlinearity in the kinetic inductance and the normal resistance of the NbN nanowire meanderline under dc current and voltage bias conditions. In the first series of experiments, the kinetic inductance has directly been measured from zero up to 99% of the critical current and to the voltage bias, where the hotspot plateau occurs. The Ginsburg-Landau (G-L) theory has been employed to justify the results. The technical procedures required to achieve our desired level of accuracy have been described in detail. In the second series of experiments, the quality factor of the NbN nanowire meanderline has been measured, providing an alternative justification to the first experimental results.

This paper reports our experimental setups to characterize the superconducting nanowire single photon detector (SNSPD) that is packaged in-house. Our packaging method ensures not only a satisfied optical coupling efficiency but also a wide band electrical connection. The packaging approach has been proved to meet the needs of cryogenic operations. The basic optoelectronic characterization results including quantum efficiency and dark count rate indicate a good agreement with the expected values.

Constructing a fault-tolerant quantum computer is a daunting task. Given any design, it is possible to determine the maximum error rate of each type of component that can be tolerated while still permitting arbitrarily large-scale quantum computation. It is an underappreciated fact that including an appropriately designed mechanism enabling long-range qubit coupling or transport substantially increases the maximum tolerable error rates of all components. With this thought in mind, we take the superconducting flux qubit coupling mechanism described in PRB 70, 140501 (2004) and extend it to allow approximately 500 MHz coupling of square flux qubits, 50 um a side, at a distance of up to several mm. This mechanism is then used as the basis of two scalable architectures for flux qubits taking into account crosstalk and fault-tolerant considerations such as permitting a universal set of logical gates, parallelism, measurement and initialization, and data mobility., 8 pages, 11 figures

Based on the variational theory, a wavelet-based numerical method is developed to calculate the defect states of acoustic waves in two-dimensional phononic crystals with point and line defects. The supercell technique is applied. By expanding the displacement field and the material constants (mass density and elastic stiffness) in periodic wavelets, the explicit formulations of an eigenvalue problem for the plane harmonic bulk waves in such a phononic structure are derived. The point and line defect states in solid-liquid and solid-solid systems are calculated. Comparisons of the present results with those measured experimentally or those from the plane wave expansion method show that the present method can yield accurate results with faster convergence and less computing time.

A wavelet-based method was developed to compute elastic band gaps of one-dimensional phononic crystals. The wave field was expanded in the wavelet basis and an equivalent eigenvalue problem was derived in a matrix form involving the adaptive computation of integrals of the wavelets. The method was then applied to a binary system. For comparison, the elastic band gaps of the same one-dimensional phononic crystals computed with the wavelet method and the well-known plane wave expansion (PWE) method are both presented in this paper. The numerical results of the two methods are in good agreement while the computation costs of the wavelet method are much lower than that of PWE method. In addition, the adaptability of wavelets makes the method possible for efficient band gap computation of more complex phononic structures.