We demonstrate a new mechanical transduction platform for individual spin qubits. In our approach, single micromagnets are trapped using a type-II superconductor in proximity of spin qubits, enabling ...direct magnetic coupling between the two systems. Controlling the distance between the magnet and the superconductor during cooldown, we demonstrate three-dimensional trapping with quality factors around 1×10^{6} and kHz trapping frequencies. We further exploit the large magnetic moment to mass ratio of this mechanical oscillator to couple its motion to the spin degrees of freedom of an individual nitrogen vacancy center in diamond. Our approach provides a new path towards interfacing individual spin qubits with mechanical motion for testing quantum mechanics with mesoscopic objects, realization of quantum networks, and ultrasensitive metrology.
We theoretically show that, despite Earnshaw's theorem, a nonrotating single magnetic domain nanoparticle can be stably levitated in an external static magnetic field. The stabilization relies on the ...quantum spin origin of magnetization, namely, the gyromagnetic effect. We predict the existence of two stable phases related to the Einstein-de Haas effect and the Larmor precession. At a stable point, we derive a quadratic Hamiltonian that describes the quantum fluctuations of the degrees of freedom of the system. We show that, in the absence of thermal fluctuations, the quantum state of the nanomagnet at the equilibrium point contains entanglement and squeezing.
We theoretically show that a magnet can be stably levitated on top of a punctured superconductor sheet in the Meissner state without applying any external field. The trapping potential created by ...such induced-only superconducting currents is characterized for magnetic spheres ranging from tens of nanometers to tens of millimeters. Such a diamagnetically levitated magnet is predicted to be extremely well isolated from the environment. We propose to use it as an ultrasensitive force and inertial sensor. A magneto-mechanical readout of its displacement can be performed by using superconducting quantum interference devices. An analysis using current technology shows that force and acceleration sensitivities on the order of 10(-23) N/root Hz (for a 100-nm magnet) and 10(-14) g/root Hz (for a 10-mm magnet) might be within reach in a cryogenic environment. Such remarkable sensitivities, both in force and acceleration, can be used for a variety of purposes, from designing ultrasensitive inertial sensors for technological applications (e.g., gravimetry, avionics, and space industry), to scientific investigations on measuring Casimir forces of magnetic origin and gravitational physics.
We describe the quantum dynamics of a magnetic rigid rotor in the mesoscopic scale where the Einstein-De Haas effect is predominant. In particular, we consider a single-domain magnetic nanoparticle ...with uniaxial anisotropy in a magnetic trap. Starting from the basic Hamiltonian of the system under the macrospin approximation, we derive a bosonized Hamiltonian describing the center-of-mass motion, the total angular momentum, and the macrospin degrees of freedom of the particle treated as a rigid body. This bosonized Hamiltonian can be approximated by a simple quadratic Hamiltonian that captures the rich physics of a nanomagnet tightly confined in position, nearly not spinning, and with its macrospin antialigned to the magnetic field. The theoretical tools derived and used here can be applied to other quantum mechanical rigid rotors.
We present the performances of a 330 g zinc molybdate (ZnMoO
4
) crystal working as scintillating bolometer as a possible candidate for a next generation experiment to search for neutrinoless double ...beta decay of
100
Mo. The energy resolution, evaluated at the 2615 keV
γ
-line of
208
Tl, is 6.3 keV FWHM. The internal radioactive contaminations of the ZnMoO
4
were evaluated as <6 μBq/kg (
228
Th) and 27±6 μBq/kg (
226
Ra). We also present the results of the
α
vs
β
/
γ
discrimination, obtained through the scintillation light as well as through the study of the shape of the thermal signal alone.
Tumor regression after antiviral therapy (AT) is in favor of an etiological role of hepatitis C virus (HCV) in non-Hodgkin's B-cell lymphomas (NHL).
We carried out a cohort study of 704 consecutive ...HIV-negative, HCV-positive patients with indolent NHL diagnosed and treated from 1993 to 2009 in 39 centers of the Fondazione Italiana Linfomi; 134 patients were managed with AT for lymphoma control.
For entire cohort, 5-year overall survival (OS) was 78% 95% confidence interval (CI): 74%–82% and 5-year progression-free survival (PFS) was 48% (95% CI: 44%–53%). In multivariate analysis, the use of AT during the patients’ life had positive impact on OS. Forty-four of the 100 patients treated with first-line AT achieved a complete remission (CR) and 33 a partial response (PR). HCV-RNA clearance was achieved in 80 patients and was related to lymphoma response. At a median follow-up of 3.6 years, 5-year PFS was 63% (95% CI: 50%–73%). CR + PR rate was 85% with AT as second-line treatment.
AT produces HCV-RNA clearance and consequent tumor regression in most patients with HCV-related indolent NHL. AT used at any time is associated with improved OS. Consequently, AT can be considered an option for patients with indolent lymphomas who do not need immediate cytoreductive treatment.
.
Archaeological Roman lead (Pb) is known to be a suitable material for shielding experimental apparata in rare event searches. In the past years the intrinsic radiopurity of this material was ...investigated using different technologies. In this work we applied the latest advancements in cryogenic techniques to study the bulk radiopurity of a 1cm^3 sample of archaeological Roman Pb. We report the lowest ever measured limit on
210
Pb content in Roman Pb, with a concentration lower than 715μBq/kg. Furthermore, we also studied
238
U and
232
Th impurity concentrations. Our values concur with independent measurements reported in literature.
•A technique for active cancellation of Pulse Tube (PT) vibrational noise is proposed.•The technique controls the relative phase of the pressure waves of two or more PTs.•A scan of the phase ...parameter space allows to find the lowest noise configuration.•The PTs are driven locking their relative phases in the optimal working condition.
The Cryogenic Underground Observatory for Rare Events (CUORE) experiment at Gran Sasso National Laboratory of INFN searches for neutrinoless double beta decay using TeO2 crystals as cryogenic bolometers. The sensitivity of the measurement heavily depends on the energy resolution of the detector, therefore the success of the experiment stands on the capability to provide an extremely low noise environment. One of the most relevant sources of noise are the mechanical vibrations induced by the five Pulse Tube cryocoolers used on the cryogenic system which houses the detectors. To address this problem, we developed a system to control the relative phases of the pulse tube pressure oscillations, in order to achieve coherent superposition of the mechanical vibrations transmitted to the detectors. In the following, we describe this method and report on the results in applying it to the CUORE system.
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