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Resistivity measurements have been made on Nb cavities, as well as on Pb and Cu, at 296, 77, and 4.2 K by means of a contactless induced-current method. For superconductors, a constant magnetic field drives the material normal below the…
We perform electric double-layer gating experiments on thin films of niobium nitride. Thanks to a cross-linked polymer electrolyte system of improved efficiency, we induce surface charge densities as high as $\approx 2.8 \times…
It is found that the magnetization curves of samples of fragments of cathode carbon deposits with a high content of multiwalled nanotubes exhibit a pronounced irreversible character, attesting to the induction of persistent currents in the…
We report on the magnetic trapping of an ultracold ensemble of $^{87}$Rb atoms close to a superconducting ring prepared in different states of quantized magnetic flux. The niobium ring of 10 $\mu$m radius is prepared in a flux state $n…
Near-field (NF) radiative heat transfer (RHT) over vacuum space between closely spaced bodies can exceed the Planck far-field (FF) values by orders of magnitude. Strong effect of superconductivity on NF RHT between plane-parallel thin-film…
Niobium thin films on silicon substrate used in the fabrication of superconducting qubits have been characterized using scanning and transmission electron microscopy, electrical transport, magnetization, quasiparticle spectroscopy, and…
Medium temperature (mid-T) baking, typically conducted at 300 350 C, enhances the quality factor of niobium (Nb) superconducting radio frequency cavities. High vacuum furnace baking is commonly preferred for its practicality in large-scale…
The superconducting circuits involving Josephson junction offer macroscopic quantum two-level system (qubit) which are coupled to cavity resonators and are operated via microwave signals. In this work, we study the dynamics of…
The efficiency of cavity sideband cooling of trapped molecules is theoretically investigated for the case where the IR transition between two rovibrational states is used as a cycling transition. The molecules are assumed to be trapped…
Superconducting microwave cavities have found applications in many areas including quantum computing, particle accelerators, and dark matter searches. Their extremely high quality factors translate to very narrow bandwidth, which makes them…
The microwave-driven dynamics of the superconducting phase difference across a Josephson junction is now widely employed in superconducting qubits and quantum circuits. With the typical energy level separation frequency of several GHz,…
The effect of mid-T heat treatment on flux trapping sensitivity was measured on several 1.3 GHz single cell cavities subjected to vacuum annealing at temperature of 150 - 400 $^\circ$C for a duration of 3 hours. The cavity was cooldown with…
This paper reports on a surface impedance measurement of a niobium titanium superconducting radio frequency (SRF) cavity in a magnetic field (up to $10\,{\rm T}$). A novel method is employed to decompose the surface resistance contributions…
A method to treat the surface of Nb is described which potentially can improve the performance of superconducting RF cavities. We present tunneling and x-ray photoemission spectroscopy (XPS) measurements at the surface of cavity-grade…
The performance of superconducting radio-frequency (SRF) cavities depends on the niobium surface condition. Recently, various heat-treatment methods have been investigated to achieve unprecedented high quality factor (Q) and high…
Vacuum thermal treatments (baking) are known to improve the superconducting properties of the RF surface layer of niobium cavities, and are employed as a last processing step to increase their efficiency determined by intrinsic quality…
The research note presents results of coupled RF and thermal simulation of a cryocooler conduction cooled 650 MHz SRF cavity made of bulk niobium and coated with Nb3Sn on the RF surface. The cavity is part of a particle accelerator design…
Point contact tunneling (PCT) spectroscopy measurements are reported over wide areas of cm-sized cut outs from niobium superconducting RF cavities. A comparison is made between a high-quality, conventionally processed (CP) cavity with a…
A detailed study of the near-surface structure and composition of Nb, the material of choice for Superconducting Radio Frequency accelerator (SRF) cavities, is of great importance in order to understand the effects of different treatments…
A Temperature mapping (T-map) system for Superconducting Radio Frequency (SRF) cavities consists of a thermometer array positioned precisely on an exterior cavity wall, capable of detecting small increases in temperature; therefore it is a…