scholarly journals Strain-spectroscopy of strongly interacting defects in superconducting qubits

2021 ◽  
Author(s):  
Octavio de los Santos ◽  
Ricardo Roman Ancheyta
Keyword(s):  
Spectral Response ◽  
Actual State ◽  
Tunnel Barrier ◽  
Superconducting Resonators ◽  
Quantum Devices ◽  
Material Defects ◽  
Spectral Signatures ◽  
Strongly Interacting ◽  
Two Level Systems ◽  
Theoretical Insight

Abstract The proper functioning of some micro-fabricated novel quantum devices, such as superconducting resonators and qubits, is severely affected by the presence of parasitic structural material defects known as tunneling two-level-systems (TLS). Recent experiments have reported unambiguous evidence of the strong interaction between individual (coherent) TLS using strain-assisted spectroscopy. This work provides an alternative and simple theoretical insight that illustrates how to obtain the spectral response of such strongly interacting defects residing inside the amorphous tunnel barrier of a qubit's Josephson junction. Moreover, the corresponding spectral signatures obtained here may serve to quickly and efficiently elucidate the actual state of these interacting TLS in experiments based on strain- or electric-field spectroscopy.

scholarly journals Forgery Detection in a Questioned Hyperspectral Document Image using K-means Clustering

2020 ◽  
Author(s):  
Maria Yaseen ◽  
Rammal Aftab ◽  
Rimsha mahrukh
Keyword(s):  
Hyperspectral Imaging ◽  
Spectral Response ◽  
Document Image ◽  
Spectral Signature ◽  
Detection Techniques ◽  
Spectral Signatures ◽  
Spectral Bands ◽  
Mismatch Detection ◽  
The One ◽  
Imaging Sensor

Hyperspectral imaging allows for analysis of images in several hundred of spectral bands depending on the spectral resolution of the imaging sensor. Hyperspectral document image is the one which has been captured by a hyperspectral camera so that the document can be observed in the different bands on the basis of their unique spectral signatures. To detect the forgery in a document various Ink mismatch detection techniques based on hyperspectral imaging have presented vast potential in differentiating visually similar inks. Inks of different materials exhibit different spectral signature even if they have the same color. Hyperspectral analysis of document images allows identification and discrimination of visually similar inks. Based on this analysis forensic experts can identify the authenticity of the document. In this paper an extensive ink mismatch detection technique is presented which uses KMean Clustering to identify different inks on the basis of their unique spectral response and separates them into different clusters.

scholarly journals Forgery Detection in a Questioned Hyperspectral Document Image using K-means Clustering

2020 ◽  
Author(s):  
Maria Yaseen ◽  
Rammal Aftab ◽  
Rimsha mahrukh
Keyword(s):  
Hyperspectral Imaging ◽  
Spectral Response ◽  
Document Image ◽  
Spectral Signature ◽  
Detection Techniques ◽  
Spectral Signatures ◽  
Spectral Bands ◽  
Mismatch Detection ◽  
The One ◽  
Imaging Sensor

Hyperspectral imaging allows for analysis of images in several hundred of spectral bands depending on the spectral resolution of the imaging sensor. Hyperspectral document image is the one which has been captured by a hyperspectral camera so that the document can be observed in the different bands on the basis of their unique spectral signatures. To detect the forgery in a document various Ink mismatch detection techniques based on hyperspectral imaging have presented vast potential in differentiating visually similar inks. Inks of different materials exhibit different spectral signature even if they have the same color. Hyperspectral analysis of document images allows identification and discrimination of visually similar inks. Based on this analysis forensic experts can identify the authenticity of the document. In this paper an extensive ink mismatch detection technique is presented which uses KMean Clustering to identify different inks on the basis of their unique spectral response and separates them into different clusters.

scholarly journals The effect of strain on tunnel barrier height in silicon quantum devices

2020 ◽  
Vol 128 (2) ◽  
pp. 024303
Author(s):  
Ryan M. Stein ◽  
M. D. Stewart
Keyword(s):  
Barrier Height ◽  
Tunnel Barrier ◽  
Quantum Devices

Optical Spectroscopy for Analysis and Monitoring of Metalworking Fluids

2018 ◽  
Vol 72 (12) ◽  
pp. 1790-1797 ◽  
Author(s):  
Johannes Kiefer ◽  
Benedikt Seidel ◽  
Daniel Meyer
Keyword(s):  
Fourier Transform ◽  
Service Life ◽  
Extended Period ◽  
Fourier Transform Infrared ◽  
Metalworking Fluids ◽  
Actual State ◽  
Spectral Signatures ◽  
Industrial Manufacturing ◽  
Oil In Water ◽  
Examination Techniques

For various industrial manufacturing processes, water-based metalworking fluids (MWFs) are of high relevance due to their cooling and lubricating ability. They commonly form oil-in-water emulsions or solutions and hence their composition and stability is crucial for their performance in the metalworking process. To ensure a long service life of the MWF, intense monitoring is obligatory. However, examination techniques which display comprehensive and precise information about the actual state of the cooling lubricant in use are currently not available. The present study aims at testing the suitability of spectroscopic methods in terms of Fourier transform infrared, Raman, and laser-induced fluorescence spectroscopy for analyzing and monitoring MWFs. It is shown that all three techniques are capable of determining the initial composition, i.e., the ratio of water and concentrate. Fourier transform infrared provides the best performance regarding monitoring the state of the fluid over an extended period of time. The spectral signatures show distinct changes during a five-month service life in a technical environment.

scholarly journals Caracterización espectral de Quillaja saponaria (Mol.)

2016 ◽  
pp. 65
Author(s):  
T. Acuña ◽  
C. Mattar ◽  
H. J. Hernández
Keyword(s):  
Vegetation Index ◽  
Near Infrared ◽  
Spectral Response ◽  
Health State ◽  
High Concentration ◽  
Health States ◽  
Plant Vigour ◽  
Quillaja Saponaria ◽  
Spectral Signatures

<p align="justify">This paper presents a spectral reflectance characterization of the specie Quillaja saponaria (Mol.), endemic tree of Chile and valued by society due to its provision of several ecosystem services that gives to society and also for its high concentration of saponins in cortex widely used in the pharmacological industry. For spectral characterization a foliar spectral signatures protocol was designed which included standardized instrumental and environmental parameters. The spectral response of different individuals was measured to evaluate the spectral behaviour and degree of variability within species in the visible and near infrared ranges (VNIR; 400-990 nm) with two hyperspectral sensors (ASD HH and camera PDF-65-V10E). The resulting spectral signatures obtained with ASD HH showed a variation less than 5% of reflectance in VNIR and lesser than that in the transition zone from red to near infrared (red-edge; 680-730 nm). Additionally, two distinctive spectral features were detected for the specie, the first is related to a fast increase of reflectance in bands 450-480 nm and the second, to a marked decrease in the 920-970 nm range associated with water absorption features. At branch level, these distinctive features are maintained but with a smaller magnitude of reflectance, which could indicate that they are useful characteristic spectral patterns that can eventually be used for monitoring the physical health state of the specie using remote sensing. On the other hand, we used a PDF-65 camera for study the plant vigour from different health states (healthy, ill, died) with spectral vegetation index. The Plant Senescence Reflectance Index detected stress on leaves, and Triangular Vegetation Index allows for a gradually characterization of every state. This work provides the first spectral reference for one of the most important sclerophyll species of Chile.</p>

scholarly journals Identification of Metal Stresses in Arabidopsis thaliana Using Hyperspectral Reflectance Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Anne M. Ruffing ◽  
Stephen M. Anthony ◽  
Lucas M. Strickland ◽  
Ian Lubkin ◽  
Carter R. Dietz
Keyword(s):  
Arabidopsis Thaliana ◽  
Metal Contamination ◽  
Near Infrared ◽  
Spectral Response ◽  
Metal Stress ◽  
Multivariate Curve Resolution ◽  
Hyperspectral Reflectance ◽  
Industrial Accidents ◽  
Spectral Signatures ◽  
Natural Flora

Industrial accidents, such as the Fukushima and Chernobyl disasters, release harmful chemicals into the environment, covering large geographical areas. Natural flora may serve as biological sensors for detecting metal contamination, such as cesium. Spectral detection of plant stresses typically employs a few select wavelengths and often cannot distinguish between different stress phenotypes. In this study, we apply hyperspectral reflectance imaging in the visible and near-infrared along with multivariate curve resolution (MCR) analysis to identify unique spectral signatures of three stresses in Arabidopsis thaliana: salt, copper, and cesium. While all stress conditions result in common stress physiology, hyperspectral reflectance imaging and MCR analysis produced unique spectral signatures that enabled classification of each stress. As the level of potassium was previously shown to affect cesium stress in plants, the response of A. thaliana to cesium stress under variable levels of potassium was also investigated. Increased levels of potassium reduced the spectral response of A. thaliana to cesium and prevented changes to chloroplast cellular organization. While metal stress mechanisms may vary under different environmental conditions, this study demonstrates that hyperspectral reflectance imaging with MCR analysis can distinguish metal stress phenotypes, providing the potential to detect metal contamination across large geographical areas.

scholarly journals Dynamical decoupling of quantum two-level systems by coherent multiple Landau–Zener transitions

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Shlomi Matityahu ◽  
Hartmut Schmidt ◽  
Alexander Bilmes ◽  
Alexander Shnirman ◽  
Georg Weiss ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Single Photon ◽  
Intrinsic Value ◽  
Bias Field ◽  
Quantum Circuits ◽  
Periodic Pattern ◽  
Superconducting Resonators ◽  
Highly Sensitive ◽  
Two Level Systems ◽  
Temperature Radiation

AbstractIncreasing and stabilizing the coherence of superconducting quantum circuits and resonators is of utmost importance for various technologies, ranging from quantum information processors to highly sensitive detectors of low-temperature radiation in astrophysics. A major source of noise in such devices is a bath of quantum two-level systems (TLSs) with broad distribution of energies, existing in disordered dielectrics and on surfaces. Here we study the dielectric loss of superconducting resonators in the presence of a periodic electric bias field, which sweeps near-resonant TLSs in and out of resonance with the resonator, resulting in a periodic pattern of Landau–Zener transitions. We show that at high sweep rates compared to the TLS relaxation rate, the coherent evolution of the TLS over multiple transitions yields a significant reduction in the dielectric loss relative to the intrinsic value. This behavior is observed both in the classical high-power regime and in the quantum single-photon regime, possibly suggesting a viable technique to dynamically decouple TLSs from a qubit.

scholarly journals Quantum sensors for microscopic tunneling systems

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Alexander Bilmes ◽  
Serhii Volosheniuk ◽  
Jan David Brehm ◽  
Alexey V. Ustinov ◽  
Jürgen Lisenfeld
Keyword(s):  
Electric Fields ◽  
Applied Strain ◽  
Control Individual ◽  
Quantum Computers ◽  
Superconducting Qubit ◽  
Low Loss ◽  
Quantum Devices ◽  
Two Level Systems ◽  
And Control ◽  
Hybrid Quantum System

AbstractThe anomalous low-temperature properties of glasses arise from intrinsic excitable entities, so-called tunneling Two-Level-Systems (TLS), whose microscopic nature has been baffling solid-state physicists for decades. TLS have become particularly important for micro-fabricated quantum devices such as superconducting qubits, where they are a major source of decoherence. Here, we present a method to characterize individual TLS in virtually arbitrary materials deposited as thin films. The material is used as the dielectric in a capacitor that shunts the Josephson junction of a superconducting qubit. In such a hybrid quantum system the qubit serves as an interface to detect and control individual TLS. We demonstrate spectroscopic measurements of TLS resonances, evaluate their coupling to applied strain and DC-electric fields, and find evidence of strong interaction between coherent TLS in the sample material. Our approach opens avenues for quantum material spectroscopy to investigate the structure of tunneling defects and to develop low-loss dielectrics that are urgently required for the advancement of superconducting quantum computers.

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