Search results for " sensor"
showing 10 items of 1714 documents
The MuPix high voltage monolithic active pixel sensor for the Mu3e experiment
2015
Mu3e is a novel experiment searching for charged lepton flavor violation in the rare decay μ → eee. In order to reduce background by up to 16 orders of magnitude, decay vertex position, decay time and particle momenta have to be measured precisely. A pixel tracker based on 50 μm thin high voltage monolithic active pixel sensors (HV-MAPS) in a magnetic field will deliver precise vertex and momentum information. Test beam results like an excellent efficiency of >99.5% and a time resolution of better than 16.6 ns obtained with the MuPix HV-MAPS chip developed for the Mu3e pixel tracker are presented.
Search for axion-like dark matter with spin-based amplifiers
2021
Ultralight axion-like particles (ALPs) are well-motivated dark matter candidates introduced by theories beyond the standard model. However, the constraints on the existence of ALPs through existing laboratory experiments are hindered by their current sensitivities, which are usually weaker than astrophysical limits. Here, we demonstrate a new quantum sensor to search for ALPs in the mass range that spans about two decades from 8.3 feV to 744 feV. Our sensor makes use of hyperpolarized long-lived nuclear spins as a pre-amplifier that effectively enhances coherently oscillating axion-like dark-matter field by a factor of >100. Using spin-based amplifiers, we achieve an ultrahigh magnetic s…
Xrase: The X-Ray Spectroscopic Explorer
2001
The X-Ray Spectroscopic Explorer (XRASE) has a unique combination of features that will make it possible to address many of NASA’s scientific goals. These include how galaxy clusters form, the physics and chemistry of the ISM, the heating of stellar coronae, the amount and content of intergalactic baryonic matter, the mass of black holes and the formation of disks and jets in AGN and galactic binaries. XRASE has a thin foil, multilayered telescope with a large collecting area up to 10 keV, especially in the Fe Kα region (1100 cm2). Its microcalorimeter array combines high energy resolution (7 eV at 6 keV) and efficiency with a field-of-view of 26 arcmin2. A deep orbit allows for long, conti…
Entanglement of superconducting qubits via microwave fields: Classical and quantum regimes
2008
We study analytically and numerically the problem of two qubits with fixed coupling irradiated with quantum or classical fields. In the classical case, we derive an effective Hamiltonian, and construct composite pulse sequences leading to a CNOT gate. In the quantum case, we show that qubit-qubit-photon multiparticle entanglement and maximally entangled two-qubit state can be obtained by driving the system at very low powers (one quanta of excitation). Our results can be applied to a variety of systems of two superconducting qubits coupled to resonators.
Surpassing the Energy Resolution Limit with Ferromagnetic Torque Sensors
2021
We discuss the fundamental noise limitations of a ferromagnetic torque sensor based on a levitated magnet in the tipping regime. We evaluate the optimal magnetic field resolution taking into account the thermomechanical noise and the mechanical detection noise at the standard quantum limit (SQL). We find that the Energy Resolution Limit (ERL), pointed out in recent literature as a relevant benchmark for most classes of magnetometers, can be surpassed by many orders of magnitude. Moreover, similarly to the case of a ferromagnetic gyroscope, it is also possible to surpass the standard quantum limit for magnetometry with independent spins, arising from spin-projection noise. Our finding indica…
Adiabatic quantum simulation with a segmented ion trap: Application to long-distance entanglement in quantum spin systems
2013
We investigate theoretically systems of ions in segmented linear Paul traps for the quantum simulation of quantum spin models with tunable interactions. The scheme is entirely general and can be applied to the realization of arbitrary spin-spin interactions. As a specific application we discuss in detail the quantum simulation of models that exhibit long-distance entanglement in the ground state. We show how tailoring of the axial trapping potential allows for generating spin-spin coupling patterns that are suitable to create long-distance entanglement. We discuss how suitable sequences of microwave pulses can implement Trotter expansions and realize various kinds of effective spin-spin int…
Long-distance entanglement and quantum teleportation in coupled-cavity arrays
2009
We introduce quantum spin models whose ground states allow for sizeable entanglement between distant spins. We discuss how spin models with global end-to-end entanglement realize quantum teleportation channels with optimal compromise between scalability and resilience to thermal decoherence, and can be implemented straightforwardly in suitably engineered arrays of coupled optical cavities.
Quantum error correction against photon loss using NOON states
2015
The so-called NOON states are quantum optical resources known to be useful especially for quantum lithography and metrology. At the same time, they are known to be very sensitive to photon losses and rather hard to produce experimentally. Concerning the former, here we present a scheme where NOON states are the elementary resources for building quantum error correction codes against photon losses, thus demonstrating that such resources can also be useful to suppress the effect of loss. Our NOON-code is an exact code that can be systematically extended from one-photon to higher-number losses. Its loss scaling depending on the codeword photon number is the same as for some existing, exact los…
Optimal control strategies for coupled quantum dots
2013
AbstractSemiconductor quantum dots are ideal candidates for quantum information applications in solid-state technology. However, advanced theoretical and experimental tools are required to coherently control, for example, the electronic charge in these systems. Here we demonstrate how quantum optimal control theory provides a powerful way to manipulate the electronic structure of coupled quantum dots with an extremely high fidelity. As alternative control fields we apply both laser pulses as well as electric gates, respectively. We focus on double and triple quantum dots containing a single electron or two electrons interacting via Coulomb repulsion. In the two-electron situation we also br…
Fast Control of Quantum States in Quantum Dots: Limits due to Decoherence
2005
We study the kinetics of confined carrier-phonon system in a quantum dot under fast optical driving and discuss the resulting limitations to fast coherent control over the quantum state in such systems.