Effective unidirectional pumping for steady-state amplification without inversion

We discuss an opportunity to achieve amplification without inversion in three-level cascade scheme using an effective unidirectional pumping via bidirectional incoherent pump. Analytical solution to the population and the coherence are obtained in the steady-state regime. With a proper choice of the parameters, obtained here, the possibility for amplification without inversion is presented.Comment: 8 Pages, 7 figure

Quantum theory of a bandpass Purcell filter for qubit readout

The measurement fidelity of superconducting transmon and Xmon qubits is partially limited by the qubit energy relaxation through the resonator into the transmission line, which is also known as the Purcell effect. One way to suppress this energy relaxation is to employ a filter which impedes microwave propagation at the qubit frequency. We present semiclassical and quantum analyses for the bandpass Purcell filter realized by E. Jeffrey et al. [Phys. Rev. Lett. 112, 190504 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.190504]. For typical experimental parameters, the bandpass filter suppresses the qubit relaxation rate by up to two orders of magnitude while maintaining the same measurement rate. We also show that in the presence of a microwave drive the qubit relaxation rate further decreases with increasing drive strength

Robust quantum state transfer using tunable couplers

We analyze the transfer of a quantum state between two resonators connected by a superconducting transmission line. Nearly perfect state-transfer efficiency can be achieved by using adjustable couplers and destructive interference to cancel the back-reflection into the transmission line at the receiving coupler. We show that the transfer protocol is robust to parameter variations affecting the transmission amplitudes of the couplers. We also show that the effects of the Gaussian filtering, pulse-shape noise, and multiple reflections on the transfer efficiency are insignificant. However, the transfer protocol is very sensitive to frequency mismatch between the two resonators. Moreover, the tunable coupler we considered produces time-varying frequency detuning caused by the changing coupling. This detuning requires an active frequency compensation with an accuracy better than 90% to yield the transfer efficiency above 99%

Robust quantum state transfer using tunable couplers

We analyze the transfer of a quantum state between two resonators connected by a superconducting transmission line. Nearly perfect state-transfer efficiency can be achieved by using adjustable couplers and destructive interference to cancel the back-reflection into the transmission line at the receiving coupler. We show that the transfer protocol is robust to parameter variations affecting the transmission amplitudes of the couplers. We also show that the effects of the Gaussian filtering, pulse-shape noise, and multiple reflections on the transfer efficiency are insignificant. However, the transfer protocol is very sensitive to frequency mismatch between the two resonators. Moreover, the tunable coupler we considered produces time-varying frequency detuning caused by the changing coupling. This detuning requires an active frequency compensation with an accuracy better than 90% to yield the transfer efficiency above 99%

Purcell effect with microwave drive: Suppression of qubit relaxation rate

We analyze the Purcell relaxation rate of a superconducting qubit coupled to a resonator, which is coupled to a transmission line and pumped by an external microwave drive. Considering the typical regime of the qubit measurement, we focus on the case when the qubit frequency is significantly detuned from the resonator frequency. Surprisingly, the Purcell rate decreases when the strength of the microwave drive is increased. This suppression becomes significant in the nonlinear regime. In the presence of the microwave drive, the loss of photons to the transmission line also causes excitation of the qubit; however, the excitation rate is typically much smaller than the relaxation rate. Our analysis also applies to a more general case of a two-level quantum system coupled to a cavity. © 2014 American Physical Society

Presence of anti-Porphyromonas gingivalis-peptidylarginine deiminase antibodies in serum from juvenile systemic lupus erythematosus patients (Letter)

Periodontal disease is a group of chronic inflammatory diseases affecting tooth-supporting tissues. The early stage is the presence of biofilm-associated gingival inflammation which, in patients having juvenile systemic lupus erythematosus (SLE), might function as a reservoir of anaerobic Gram-negative bacteria such as Porphyromonas gingivalis. Porphyromonas gingivalis has been associated with an increased level of anticardiolipin and anti-b2-glycoprotein antibodies in patients with SLE, which implies periodontal disease as a modifiable risk factor for SLE morbility1 . Besides, Porphyromonas gingivalis also express functional endogenous Peptidylarginine deiminase (PAD) enzymes, which catalyzes a citrullination reaction that can lead to formation of citrullinated peptides. PAD can frequently be recognized in sera of patients with rheumatoid arthritis, systemic lupus erythematosusand primary Sjögren syndrome2 . Laugisch et al. 3 reported that PAD secreted by Porphyromonas gingivalis (PPAD) from patients having rheumatoid arthritis and periodontal disease may exert its citrullinating activity in distant regions of the periodontium. Although the relevance of PADs to the pathogenesis of SLE has been wellreported4,5 to the best of our knowledge, no evidence for the presence of PPAD in patients having SLE has been reportedFull Tex

Clinical, immunological and microbial gingival profile of juvenile systemic lupus erythematosus patients

Periodontal disease has been associated with rheumatic diseases; however, few studies have evaluated the association with systemic lupus erythematosus (SLE), and its impact on the local inflammatory and microbial profiles. Therefore, this study evaluated the levels of several cytokines in gingival crevicular fluid (GCF) and serum from juvenile SLE (jSLE) patients with gingival inflammation, compared with controls. In addition, we assessed their subgingival microbial profile. Thirty jSLE patients and 29 systemically healthy individuals were recruited. Participants were rheumatologically and periodontally examined, and GCF, serum and intrasulcular biofilm were collected. Cytokines were analysed by bead-based multiplex assays and the bacterial profile by checkerboard DNA–DNA hybridization. jSLE patients presented higher percentages of dental plaque and bleeding than controls, as well as increased mean probing depth and attachment loss. After adjustment for multiple comparisons, GCF levels of interleukin (IL)-1β, IL-8, granulocyte colony-stimulating factor (G-CSF), interferon-γ and monocyte chemoattractant protein-1 were significantly higher, whereas the levels of granulocyte–macrophage colony-stimulating factor were significantly lower in jSLE patients. In serum, G-CSF levels tended to be higher in jSLE patients (adjusted p-value = 0.06). Intrasulcular counts of Aggregatibacter actinomycetemcomitans were significantly higher in jSLE patients as compared with controls. We conclude that patients with jSLE present a worse periodontal condition associated with altered levels of pro-inflammatory cytokines in GCF and increased counts of A. actinomycetemcomitans in the intrasulcular biofilm.No Full Tex

Impact of chronic gingivitis management on the cytokine and anti-PPAD expressions in juvenile systemic lupus erythematosus: A six-month follow-up

Objective: To evaluate how chronic gingivitis treatment impacts the oral and circulating cytokine expressions after six-month follow-up in patients with juvenile systemic lupus erythematosus (jSLE) and also to evaluate the circulating expression of anti-Porphyromonas gingivalis peptidylarginine deiminase antibodies (anti-PPAD) before and after treatment. Background: Juvenile systemic lupus erythematosus patients present a worse periodontal condition associated with higher gingival crevicular fluid (GCF) levels of interleukin (IL)-1β, IL-8, granulocyte colony-stimulating factor (G-CSF), interferon-γ and monocyte chemoattractant protein (MCP)-1. Materials and Methods: Twenty-one adolescents with jSLE (mean age: 16.2 ± 1.5 years) were recruited. Participants were rheumatologically and periodontally examined. All individuals were clinically diagnosed with gingival inflammation. Chronic gingivitis treatment consisted of supragingival scaling, prophylaxis and oral hygiene instructions. The cytokine levels were determined by bead-based multiplex assays and the anti-PPAD levels by ELISA. Gingival crevicular fluid (GCF) and serum samples were collected at baseline and 6 months after treatment. Results: We observed a reduction in attachment loss, SLE Disease Activity Index (SLEDAI), IL-1β, IL-10 and MCP-1 GCF levels, and the IL-4 and IL-5 serum levels 6 months after periodontal treatment. On the contrary, a significant increase in GCF expression of IL-4, IL-12, IL-17, IFN-γ and serum levels of anti-PPAD antibody was observed. Conclusion: Juvenile systemic lupus erythematosus patients seem to positively benefit from periodontal treatment by a significantly reduced CAL, a GCF reduction of pro-inflammatory cytokines and an increasing of anti-inflammatory ones. However, an increase in the GCF expression of IL-17 and the serum expression of anti-PPAD antibody 6 months after periodontal treatment might negatively affect the treatment outcome of such patients in the long term.Full Tex