From quantum coherence to nonclassicality and metrological power

2019 ◽  
Author(s):  
Kok Chuan Bobby Tan ◽  
Hyunseok Jeong ◽  
Tyler Volkoff ◽  
Hyukjoon Kwon
Keyword(s):  
Quantum Coherence

Engineering Electronic Structure to Protect Phase Memory in Molecular Qubits by Minimising Orbital Angular Momentum

2018 ◽  
Author(s):  
Ana Maria Ariciu ◽  
David H. Woen ◽  
Daniel N. Huh ◽  
Lydia Nodaraki ◽  
Andreas Kostopoulos ◽  
...  
Keyword(s):  
Electron Spin ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Pulse Sequences ◽  
Grover Algorithm ◽  
Ligand Shell ◽  
Information Strategies ◽  
Spin Qubit ◽  
Molecular Spin ◽  
The Impact

Using electron spins within molecules for quantum information processing (QIP) was first proposed by Leuenberger and Loss (1), who showed how the Grover algorithm could be mapped onto a Mn12 cage (2). Since then several groups have examined two-level (S = ½) molecular spin systems as possible qubits (3-12). There has also been a report of the implementation of the Grover algorithm in a four-level molecular qudit (13). A major challenge is to protect the spin qubit from noise that causes loss of phase information; strategies to minimize the impact of noise on qubits can be categorized as corrective, reductive, or protective. Corrective approaches allow noise and correct for its impact on the qubit using advanced microwave pulse sequences (3). Reductive approaches reduce the noise by minimising the number of nearby nuclear spins (7-11), and increasing the rigidity of molecules to minimise the effect of vibrations (which can cause a fluctuating magnetic field via spin-orbit coupling) (9,11); this is essentially engineering the ligand shell surrounding the electron spin. A protective approach would seek to make the qubit less sensitive to noise: an example of the protective approach is the use of clock transitions to render spin states immune to magnetic fields at first order (12). Here we present a further protective method that would complement reductive and corrective approaches to enhancing quantum coherence in molecular qubits. The target is a molecular spin qubit with an effective 2S ground state: we achieve this with a family of divalent rare-earth molecules that have negligible magnetic anisotropy such that the isotropic nature of the electron spin renders the qubit markedly less sensitive to magnetic noise, allowing coherent spin manipulations even at room temperature. If combined with the other strategies, we believe this could lead to molecular qubits with substantial advantages over competing qubit proposals.<br>

Expression and Solution NMR Study of Multi-site Phosphomimetic Mutant BCL-2 Protein

2019 ◽  
Vol 26 (6) ◽  
pp. 449-457
Author(s):  
Ting Song ◽  
Keke Cao ◽  
Yu dan Fan ◽  
Zhichao Zhang ◽  
Zong W. Guo ◽  
...  
Keyword(s):  
Structural Change ◽  
Structural Biology ◽  
Quantum Coherence ◽  
Structural Changes ◽  
Solution Nmr ◽  
Flexible Loop ◽  
Loop Region ◽  
Loop Domain ◽  
Nmr Study ◽  
Binding Groove

Background: The significance of multi-site phosphorylation of BCL-2 protein in the flexible loop domain remains controversial, in part due to the lack of structural biology studies of phosphorylated BCL-2. Objective: The purpose of the study is to explore the phosphorylation induced structural changes of BCL-2 protein. Methods: We constructed a phosphomietic mutant BCL-2(62-206) (t69e, s70e and s87e) (EEEBCL- 2-EK (62-206)), in which the BH4 domain and the part of loop region was truncated (residues 2-61) to enable a backbone resonance assignment. The phosphorylation-induced structural change was visualized by overlapping a well dispersed 15N-1H heteronuclear single quantum coherence (HSQC) NMR spectroscopy between EEE-BCL-2-EK (62-206) and BCL-2. Results: The EEE-BCL-2-EK (62-206) protein reproduced the biochemical and cellular activity of the native phosphorylated BCL-2 (pBCL-2), which was distinct from non-phosphorylated BCL-2 (npBCL-2) protein. Some residues in BH3 binding groove occurred chemical shift in the EEEBCL- 2-EK (62-206) spectrum, indicating that the phosphorylation in the loop region induces a structural change of active site. Conclusion: The phosphorylation of BCL-2 induced structural change in BH3 binding groove.

scholarly journals Optimization of Lignin Extraction Variables by Response Surface Methodology from Pine Saw Dust, and Quantification of Major Structural Units in Isolated Lignin Fraction

2021 ◽  
Vol 11 (4) ◽  
pp. 1739
Author(s):  
Muhammad Ajaz Ahmed ◽  
Jae Hoon Lee ◽  
Joon Weon Choi
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Quantum Coherence ◽  
Resonance Spectrum ◽  
Quadratic Model ◽  
Molecular Weights ◽  
Solids Loading ◽  
A Value ◽  
Lignin Extraction ◽  
Lignin Fraction

A synergistic combination of dioxane, acetic acid, and HCl was investigated for lignin extraction from pine wood biomass. After initial screening of reagent combination, response surface methodology (RSM) was used to optimize the lignin yield with respect to the variables of time 24–72 h, solids loading 5–15%, and catalyst dose 5–15 mL. A quadratic model predicted 8.33% of the lignin yield, and it was further confirmed experimentally and through the analysis of variance (ANOVA). Lignin at optimum combination exhibited features in terms of derivatization followed by reductive cleavage (DFRC) with a value of (305 µmol/gm), average molecular weights of 4358 and polydispersity of 1.65, and 2D heteronuclear single quantum coherence nuclear magnetic resonance spectrum (2D-HSQC NMR) analysis showing relative β-O-4 linkages (37.80%). From here it can be suggested that this fractionation can be one option for high quality lignin extraction from lignocellulosic biomass.

scholarly journals N-[7-Chloro-4-[4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl] quinoline]-acetamide

Molbank ◽  
10.3390/m1213 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1213
Author(s):  
Paolo Coghi ◽  
Jerome P. L. Ng ◽  
Ali Adnan Nasim ◽  
Vincent Kam Wai Wong
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Coherence ◽  
Biologically Active ◽  
Proton Nuclear Magnetic Resonance ◽  
Dipolar Cycloaddition ◽  
Heteronuclear Single Quantum Coherence ◽  
Pharmacokinetic Properties ◽  
Nuclear Magnetic

The 1,2,3-triazole is a well-known biologically active pharmacophore constructed by the copper-catalyzed azide–alkyne cycloaddition. We herein reported the synthesis of 4-amino-7-chloro-based [1,2,3]-triazole hybrids via Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of 4-azido-7-chloroquinoline with an alkyne derivative of acetaminophen. The compound was fully characterized by Fourier-transform infrared (FTIR), proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), heteronuclear single quantum coherence (HSQC), ultraviolet (UV) and high-resolution mass spectroscopies (HRMS). This compound was screened in vitro with different normal and cancer cell lines. The drug likeness of the compound was also investigated by predicting its pharmacokinetic properties.

scholarly journals Characterization of multilevel quantum coherence without ideal measurements

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Benjamin Dive ◽  
Nikolaos Koukoulekidis ◽  
Stefanos Mousafeiris ◽  
Florian Mintert
Keyword(s):  
Quantum Coherence
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