121615838
SQUIDs, Brains and Gravity Waves
▸ A lonely instrument in Baja California records tiny fluctuations in the Earth's magnetic field, giving valuable information on the location of geothermal energy.▸ An extremely quiet amplifier detects electrical noise generated by the fluctuating spins in a collection of chlorine nuclei—the first observation of nuclear‐spin noise.▸ Superconducting gradiometers in liquid helium measure tiny fluctuating magnetic fields emanating from the human brain (see figure 1), pinpointing the source of the electrical discharge associated with focal epilepsy.▸ An aluminum bar weighing 4800 kg and cooled to 4.2 K rests in a vacuum chamber at Stanford University, working as the world's most sensitive monitor of gravitational radiation.
119996004
Quantum-noise theory for the resistively shunted josephson junction
We show that the low-frequency spectral density of the voltage noise in a current-biased Josephson junction with critical current I/sub o/, shunt resistance R, and small capacitance is eI/sub 0//sup ts2/R/sup 3//..pi..V in the limit eV>>k/sub B/T(I/I/sub o/)/sup 2/ and I>I/sub o/, where V is the voltage and I is the current. The noise arises from zero-point current fluctuations in the shunt resistor. The rounding of the current-voltage characteristic caused by the quantum fluctuations and the effects of nonzero junction capacitance are calculated.
121524547
EXPERIMENTAL COMPARISON OF THE JOSEPHSON VOLTAGE--FREQUENCY RELATION IN DIFFERENT SUPERCONDUCTORS.
209807988
SQUIDS: PRINCIPLES, NOISE, AND APPLICATIONS
120441847
SQUIDs: THEN AND NOW
Following Brian Josephson's prediction in 1962, Anderson and Rowell observed Josephson tunneling in 1963. The following year, Jaklevic, Lambe, Silver and Mercereau demonstrated quantum interference in a superconducting ring containing two Josephson tunnel junctions. Subsequently, the first practical devices emerged, including the point-contact dc and rf SQUIDs (Superconducting QUantum Interference Devices) of Zimmerman and Silver and Clarke's SLUG (Superconducting Low-inductance Undulatory Galvanometer) — a blob of solder frozen around a length of niobium wire. The return to the tunnel junction as the Josephson element was heralded by the cylindrical SQUID in 1976. The square washer dc SQUID developed by Ketchen and Jaycox in 1982 remains the workhorse design for most applications. Theories for the dc and rf SQUIDs were worked out in the 1970s. Today, SQUIDs (mostly dc) are used in a variety of configurations — for example, as magnetometers, gradiometers, cryogenic current comporators, low-frequency and m...
13674438
Galaxy Cluster Scaling Relations Measured with APEX-SZ
We present thermal Sunyaev-Zel'dovich effect (SZE) measurements for 42 galaxy clusters observed at 150 GHz with the APEX-SZ experiment. For each cluster, we model the pressure profile and calculate the integrated Comptonization Y to estimate the total thermal energy of the intraclustermedium (ICM). We compare the measured Y values to X-ray observables of the ICM from the literature (cluster gas mass M-gas, temperature T-X, and Y-X = MgasTX) that relate to total cluster mass. We measure power-law scaling relations, including an intrinsic scatter, between the SZE and X-ray observables for three subsamples within the set of 42 clusters that have uniform X-ray analysis in the literature. We observe that differences between these X-ray analyses introduce significant variance into the measured scaling relations, particularly affecting the normalization. For all three subsamples, we find results consistent with a selfsimilarmodel of cluster evolution dominated by gravitational effects. Comparing to predictions from numerical simulations, these scaling relations prefer models that include cooling and feedback in the ICM. Lastly, we measure an intrinsic scatter of similar to 28 per cent in the Y - Y-X scaling relation for all three subsamples.
118677819
Testing radiative neutrino mass models at the LHC
A bstractThe Large Hadron Collider provides us new opportunities to search for the origin of neutrino mass. Beyond the minimal see-saw models a plethora of models exist which realise neutrino mass at tree- or loop-level, and it is important to be sure that these possibilities are satisfactorily covered by searches. The purpose of this paper is to advance a systematic approach to this problem. Majorana neutrino mass models can be organised by SM-gauge-invariant operators which violate lepton number by two units. In this paper we write down the minimal ultraviolet completions for all of the mass-dimension 7 operators. We predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged scalar, a scalar doublet, and a scalar quadruplet, whose properties are constrained by neutrino oscillation data. A detailed collider study is presented for O3=LLQd¯H$$ {\mathcal{O}}_3=LLQ\overline{d}H $$ and O8=Ld¯e¯†u¯†H$$ {\mathcal{O}}_8=L\overline{d}{\overline{e}}^{\dagger }{\overline{u}}^{\dagger }H $$ completions with a vector-like quark χ∼3,2,−56$$ \chi \sim \left(3,2,-\frac{5}{6}\right) $$ and a leptoquark ϕ∼3¯113$$ \phi \sim \left(\overline{3},1,\frac{1}{3}\right) $$. The existing LHC limits extracted from searches for vector-like fermions and sbottoms/stops are mχ ≳ 620 GeV and mϕ ≳ 600 GeV.