65 research outputs found
Detecting magnetically guided atoms with an optical cavity
We show that a low finesse cavity can be efficient for detecting neutral
atoms. The low finesse can be compensated for by decreasing the mode waist of
the cavity. We have used a near concentric resonator with a beam waist of
12m and a finesse of only 1100 to detect magnetically guided Rb atoms with
a detection sensitivity of 0.1 atom in the mode volume. For future experiments
on single atom detection and cavity QED applications, it should be very
beneficial to use miniaturized optical resonator integrated on atom chips.Comment: To appear in Optics Letter
Influence of plastic deformation on the defective structure of TI-6AL-4V
The influence of plastic deformation on the defect structure of Ti-6Al-4V titanium alloy was investigated. X-ray analysis was performed with interpretation of the diffractogram reflections and determination of the parameters of the crystal structure. The data obtained were used to calculate the dislocation density of a titanium alloy after cold-rolled plastic deformation
General simulation method for quantum-sensing systems
Quantum sensing encompasses highly promising techniques with diverse
applications including noise-reduced imaging, super-resolution microscopy as
well as imaging and spectroscopy in challenging spectral ranges. These
detection schemes use biphoton correlations to surpass classical limits or
transfer information to different spectral ranges. Theoretical analysis is
mostly confined to idealized conditions. Therefore, theoretical predictions and
experimental results for the performance of quantum-sensing systems often
diverge. Here we present a general simulation method that includes experimental
imperfections to bridge the gap between theory and experiment. We develop a
theoretical approach and demonstrate the capabilities with the simulation of
aligned and misaligned quantum-imaging experiments. The results recreate the
characteristics of experimental data. We further use the simulation results to
improve the obtained images in post-processing. As simulation method for
general quantum-sensing systems, this work provides a first step towards
powerful simulation tools for interactively exploring the design space and
optimizing the experiment's characteristics.Comment: 19 pages, 8 figure
Security Analysis of CPace
In response to standardization requests regarding password-authenticated key exchange (PAKE) protocols, the IRTF working group CFRG has setup a PAKE selection process in 2019, which led to the selection of the CPace protocol in the balanced setting, in which parties share a common password. In subsequent standardization efforts, the CPace protocol further developed, yielding a protocol family whose actual security guarantees in practical settings are not well understood. In this paper, we provide a comprehensive security analysis of CPace in the universal composability framework. Our analysis is realistic in the sense that it captures adaptive corruptions and refrains from modeling CPace's Map2Pt function that maps field elements to curve points as an idealized function. In order to extend our proofs to different CPace variants optimized for specific elliptic-curve ecosystems, we employ a new approach which represents the assumptions required by the proof as libraries accessed by a simulator. By allowing for the modular replacement of assumptions used in the proof, this new approach avoids a repeated analysis of unchanged protocol parts and lets us efficiently analyze the security guarantees of all the different CPace variants. As a result of our analysis, all of the investigated practical CPace variants enjoy adaptive UC security
A simple integrated single-atom detector
We present a reliable and robust integrated fluorescence detector capable of
detecting single atoms. The detector consists of a tapered lensed single-mode
fiber for precise delivery of excitation light and a multimode fiber to collect
the fluorescence. Both are mounted in lithographically defined SU-8 holding
structures on an atom chip. Rb87 atoms propagating freely in a magnetic guide
are detected with an efficiency of up to 66%, and a signal-to-noise ratio in
excess of 100 is obtained for short integration times.Comment: 3 pages, 3 figure
SoK: SCA-secure ECC in software – mission impossible?
This paper describes an ECC implementation computing the X25519 keyexchange protocol on the Arm Cortex-M4 microcontroller. For providing protections against various side-channel and fault attacks we first review known attacks and countermeasures, then we provide software implementations that come with extensive mitigations, and finally we present a preliminary side-channel evaluation. To our best knowledge, this is the first public software claiming affordable protection against multiple classes of attacks that are motivated by distinct real-world application scenarios. We distinguish between X25519 with ephemeral keys and X25519 with static keys and show that the overhead to our baseline unprotected implementation is about 37% and 243%, respectively. While this might seem to be a high price to pay for security, we also show that even our (most protected) static implementation is at least as efficient as widely-deployed ECC cryptographic libraries, which offer much less protection
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