اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدDesign and Characterization of a Field-Switchable Nanomagnetic Atom Mirror
234
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present a design for a switchable nanomagnetic atom mirror formed by an array of 180{deg} domain walls confined within Ni80Fe20 planar nanowires. A simple analytical model is developed which allows the magnetic field produced by the domain wall array to be calculated. This model is then used to optimize the geometry of the nanowires so as to maximize the reflectivity of the atom mirror. We then describe the fabrication of a nanowire array and characterize its magnetic behavior using magneto-optic Kerr effect magnetometry, scanning Hall probe microscopy and micromagnetic simulations, demonstrating how the mobility of the domain walls allow the atom mirror to be switched on and off in a manner which would be impossible for conventional designs. Finally, we model the reflection of 87Rb atoms from the atom mirrors surface, showing that our design is well suited for investigating interactions between domain walls and cold atoms.
قيم البحث
اقرأ أيضاً
We describe a robust and reliable fluorescence detector for single atoms that is fully integrated into an atom chip. The detector allows spectrally and spatially selective detection of atoms, reaching a single atom detection efficiency of 66%. It con
sists of a tapered lensed single-mode fiber for precise delivery of excitation light and a multi-mode fiber to collect the fluorescence. The fibers are mounted in lithographically defined holding structures on the atom chip. Neutral 87Rb atoms propagating freely in a magnetic guide are detected and the noise of their fluorescence emission is analyzed. The variance of the photon distribution allows to determine the number of detected photons / atom and from there the atom detection efficiency. The second order intensity correlation function of the fluorescence shows near-perfect photon anti-bunching and signs of damped Rabi-oscillations. With simple improvements one can boost the detection efficiency to > 95%.
The dimensionality of an electronic quantum system is decisive for its properties. In 1D electrons form a Luttinger liquid and in 2D they exhibit the quantum Hall effect. However, very little is known about the behavior of electrons in non-integer, i
.e. fractional dimensions. Here, we show how arrays of artificial atoms can be defined by controlled positioning of CO molecules on a Cu(111) surface, and how these sites couple to form electronic Sierpinski fractals. We characterize the electron wavefunctions at different energies with scanning tunneling microscopy and spectroscopy and show that they inherit the fractional dimension. Wavefunctions delocalized over the Sierpinski structure decompose into self-similar parts at higher energy, and this scale invariance can also be retrieved in reciprocal space. Our results show that electronic quantum fractals can be man-made by atomic manipulation in a scanning tunneling microscope. The same methodology will allow to address fundamental questions on the effects of spin-orbit interaction and a magnetic field on electrons in non-integer dimensions. Moreover, the rational concept of artificial atoms can readily be transferred to planar semiconductor electronics, allowing for the exploration of electrons in a well-defined fractal geometry, including interactions and external fields.
We investigate the Landau-Zener-Stuckelberg-Majorana interferometry of a superconducting qubit in a semi-infinite transmission line terminated by a mirror. The transmon-type qubit is at the node of the resonant electromagnetic (EM) field, hiding from
the EM field. Mirror, mirror briefly describes this system, because the qubit acts as another mirror. We modulate the resonant frequency of the qubit by applying a sinusoidal flux pump. We probe the spectroscopy by measuring the reflection coefficient of a weak probe in the system. Remarkable interference patterns emerge in the spectrum, which can be interpreted as multi-photon resonances in the dressed qubit. Our calculations agree well with the experiments.
Nanomagnetic logic is an energy efficient computing architecture that relies on the dipole field coupling of neighboring magnets to transmit and process binary information. In this architecture, nanomagnet chains act as local interconnects. To assess
the merits of this technology, the speed and reliability of magnetic signal transmission along these chains must be experimentally determined. In this work, time-resolved pump-probe x-ray photo-emission electron microscopy is used to observe magnetic signal transmission along a chain of nanomagnets. We resolve successive error-free switching events in a single nanomagnet chain at speeds on the order of 100 ps per nanomagnet, consistent with predictions based on micromagnetic modeling. Errors which disrupt transmission are also observed. We discuss the nature of these errors, and approaches for achieving reliable operation.
Single-photon sources that emit photons at the same energy play a key role in the emerging concepts of quantum information, such as entanglement swapping, quantum teleportation and quantum networks. They can be realized in a variety of systems, where
semiconductor quantum dots, or artificial atoms, are arguably among the most attractive. However, unlike natural atoms, no two artificial atoms are alike. This peculiarity is a serious hurdle for quantum information applications that require photonic quantum states with identical energies. Here we demonstrate a single artificial atom that generates photons with an absolute energy that is locked to an optical transition in a natural atom. Furthermore, we show that our system is robust and immune to drifts and fluctuations in the environment of the emitter. Our demonstration is crucial for realization of a large number of universally-indistinguishable solid-state systems at arbitrary remote locations, where frequency-locked artificial atoms might become fundamental ingredients.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
