44 research outputs found
Josephson oscillation linewidth of ion-irradiated YBaCuO junctions
We report on the noise properties of ion-irradiated YBaCuO
Josephson junctions. This work aims at investigating the linewidth of the
Josephson oscillation with a detector response experiment at 132 GHz.
Experimental results are compared with a simple analytical model based on the
Likharev-Semenov equation and the de Gennes dirty limit approximation. We show
that the main source of low-frequency fluctuations in these junctions is the
broadband Johnson noise and that the excess () noise contribution
does not prevail in the temperature range of interest, as reported in some
other types of high-T superconducting Josephson junctions. Finally, we
discuss the interest of ion-irradiated junctions to implement frequency-tunable
oscillators consisting of synchronized arrays of Josephson junctions
New Results from HAYSTAC's Phase II Operation with a Squeezed State Receiver
A search for dark matter axions with masses has been
performed using the HAYSTAC experiment's squeezed state receiver to achieve
sub-quantum limited noise. This report includes details of the design and
operation of the experiment previously used to search for axions in the mass
ranges and (GHz) and
GHz) as well as upgrades to facilitate an extended search at
higher masses. These upgrades include improvements to the data acquisition
routine which have reduced the effective dead time by a factor of 5, allowing
for the new region to be scanned 1.6 times faster with comparable
sensitivity. No statistically significant evidence of an axion signal is found
in the range (GHz), leading to an
aggregate upper limit exclusion at the level on the axion-photon
coupling of .Comment: 20 pages, 16 figure
Emerging roles of ATF2 and the dynamic AP1 network in cancer
Cooperation among transcription factors is central for their ability to execute specific transcriptional programmes. The AP1 complex exemplifies a network of transcription factors that function in unison under normal circumstances and during the course of tumour development and progression. This Perspective summarizes our current understanding of the changes in members of the AP1 complex and the role of ATF2 as part of this complex in tumorigenesis.Fil: Lopez Bergami, Pablo Roberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BiologĂa y Medicina Experimental (i); Argentina; ArgentinaFil: Lau, Eric . Burnham Institute for Medical Research; Estados UnidosFil: Ronai, Zeev . Burnham Institute for Medical Research; Estados Unido