Quantum noise limited microwave amplification using a graphene Josephson junction

Josephson junctions (JJ) and their tunable properties, including their nonlinearities, form the core of superconducting circuit quantum electrodynamics (cQED). In quantum circuits, low-noise amplification of feeble microwave signals is essential and the Josephson parametric amplifiers (JPA) are the widely used devices. The existing JPAs are based on Al-AlOx-Al tunnel junctions realized in a superconducting quantum interference device geometry, where magnetic flux is the knob for tuning the frequency. Recent experimental realizations of 2D van der Waals JJs provide an opportunity to implement various cQED devices with the added advantage of tuning the junction properties and the operating point using a gate potential. While other components of a possible 2D van der Waals cQED architecture have been demonstrated -- quantum noise limited amplifier, an essential component, has not been realized. Here we implement a quantum noise limited JPA, using a graphene JJ, that has linear resonance gate tunability of 3.5 GHz. We report 24 dB amplification with 10 MHz bandwidth and -130 dBm saturation power; performance on par with the best single-junction JPAs. Importantly, our gate tunable JPA works in the quantum-limited noise regime which makes it an attractive option for highly sensitive signal processing. Our work has implications for novel bolometers -- the low heat capacity of graphene together with JJ nonlinearity can result in an extremely sensitive microwave bolometer embedded inside a quantum noise-limited amplifier. In general, our work will open up exploration of scalable device architecture of 2D van der Waals materials by integrating a sensor with the quantum amplifier.Comment: 15 pages, 4 figures, and supplementary informatio

Hepatoprotective activity of hydroalcoholic extract of leaves of <i style="">Alocasia indica</i> (Linn.)<i style=""></i>

816-821Oral administration of hydroalcoholic extract of A. indica (250 and 500 mg/kg) effectively inhibited CCl4 and paracetamol induced changes in the serum marker enzymes, cholesterol, serum protein and albumin in a dose-dependent manner as compared to the normal and the standard drug silymarin-treated groups. Hepatic steatosis, fatty infiltration, hydropic degeneration and necrosis observed in CCl4 and paracetamol-treated groups were completely absent in histology of the liver sections of the animals treated with the extracts. The results suggests that the hydroalcoholic extract of leaves of A. indica possess significant potential as hepatoprotective agent.</b

Multiplexed readout of four qubits in 3D circuit QED architecture using a broadband Josephson parametric amplifier

We propose and demonstrate a frequency-multiplexed readout scheme in 3D circuit-quantum electrodynamics (cQED) architecture. We use four transmon qubits coupled to individual rectangular cavities which are aperture-coupled to a common rectangular waveguide feedline. A coaxial to waveguide transformer at the other end of the feedline allows one to launch and collect the multiplexed signal. The reflected readout signal is amplified by an impedance-engineered broadband parametric amplifier with 380 MHz bandwidth. This provides us high fidelity single-shot readout of multiple qubits using compact microwave circuitry, an efficient way for scaling up to more qubits in 3D cQE

Proceedings of National Conference on Relevance of Engineering and Science for Environment and Society

This conference proceedings contains articles on the various research ideas of the academic community and practitioners presented at the National Conference on Relevance of Engineering and Science for Environment and Society (R{ES}2 2021). R{ES}2 2021 was organized by Shri Pandurang Pratishthan’s, Karmayogi Engineering College, Shelve, Pandharpur, India on July 25th, 2021. Conference Title: National Conference on Relevance of Engineering and Science for Environment and SocietyConference Acronym: R{ES}2 2021Conference Date: 25 July 2021Conference Location: Online (Virtual Mode)Conference Organizers: Shri Pandurang Pratishthan’s, Karmayogi Engineering College, Shelve, Pandharpur, India