15 research outputs found
Normal-mode splitting in the optomechanical system with an optical parametric amplifier and coherent feedback
Strong coupling in optomechanical systems is the basic condition for
observing many quantum phenomena such as optomechanical squeezing and
entanglement. Normal-mode splitting (NMS) is the most evident signature of
strong coupling systems. Here we show the NMS in the spectra of the movable
mirror and the output field in an optomechanical system can be flexibly
engineered by a combination of optical parametric amplifier (OPA) and coherent
feedback (CF). Moreover, the NMS could be enhanced by optimizing the parameters
such as input optical power, OPA gain and phase, CF strength in terms of
amplitude reflectivity of beam splitter.Comment: 8 pages, 7 figure
Precision Enhancement in Spatial Measurement by Introducing Squeezed Light into Weak Value Amplification
The precision enhancement is demonstrated in an optical spatial measurement
based on weak value amplification (WVA) system and split-like detection, by
injecting a TEM10 squeezed vacuum beam. It is the first time combining the WVA
technique and squeezed beam injection to experimentally realize high-precision
optical spatial measurement beyond the standard quantum limit. As a result, the
precision enhancement of 1.3 times can be achieved at 500kHz by adding a
squeezed beam in the vacuum input port of the Mach-Zehnder interferometer. The
minimum measurable displacement is reduced from 1.08pm to 0.85pm and the
corresponding minimum measurable tilt is reduced from 0.86prad to 0.67prad.
Moreover, the spatial measurement at low-frequency band is also implemented and
the SNR is improved 2dB at 4kHz. Our work provides an effective method to
accomplish higher precision in optical spatial measurement, which has potential
applications in gravitational wave interferometer calibration, super-resolution
quantum imaging, etc.Comment: 4 pages, 5 figures
(H, Li)Cl and LiOH hydration : surface tension, solution conductivity and viscosity, and exothermic dynamics
We systematically examined the effect of (H, Li)Cl and LiOH solvation on the O:H[sbnd]O bond network deformation, surface tension (contact angle), solution electrical conductivity, thermomics, and viscosity evolution aiming to clarifying the functionalities for ions, lone pairs, and protons acting in these solutions. Results confirmed that H + and electron lone pair ā:ā introduction turns out the (H 3 O + , OH ā )Ā·4H 2 O motifs and that the Li + and Cl ā form each a hydration volume through the screened electrostatic polarization. The (H 3 O + , OH ā )Ā·4H 2 O turns an O:H[sbnd]O bond into the H ā H antiāHB that disrupts the HCl solution network and its surface tension and into the O:ā:O superāHB compressor that raises the LiOH solution surface tension and viscosity, as well as the solution temperature during solvation. The Li + /Cl ā ion reserves/reduces its hydration volume because of the complete/incomplete screen shielding by the ordered hydrating H 2 O dipoles and the Cl ā ā Cl ā repulsion at higher concentrations. The invariant/variant Li + /Cl ā hydration volume dictates, respectively, the linear/nonlinear concentration dependence of the JonesāDole viscosity. Except for the HCl/H 2 O surface tension and LiOH/H 2 O viscosity, the conductivity, surface tension, and viscosity of these solutions follow the JonesāDole notion that underscores the faction of bond transition from the mode of water to hydration.Accepted versio
Discriminative ionic capabilities on hydrogen-bond transition from the mode of ordinary water to (Mg, Ca, Sr)(Cl, Br)ā hydration
It has been a long pursuit to discriminate the ionic roles of mono- and di-valent salt solutions in modulating the hydrogen bonding network and solution properties. We attended this issue by examining the effect of concentrated YX 2 (Y[dbnd]Mg, Ca, Sr; X[dbnd]Cl, Br) solvation on O:HāO bonds transition from the mode of ordinary water to hydration in terms of the number fraction f YX2 (C) and the segmental O:HāO bond phonon stiffness shift ĪĻ(C) with C being the solute concentration. The invariant df Y (C) / dC at C ā¤ <0.05 suggests that the small Y 2+ forms a constantly-sized hydration droplet with weak responding to interference of other ions because its hydrating H 2 O dipoles screen mostly its electric field. However, the number inadequacy of the highly-ordered hydrating H 2 O dipoles partially screens the large X ā . The X ā ā X ā electrostatic repulsion weakens its electric field. The concentration-trend consistency of the f YX2 (C), the solution conductivity Ļ YX2 (C), and surface stress (contact angle) Īø YX2 (C) for YX 2 solutions clarifies their common origin of ionic polarization. However, the JonesāDale notion disobedience of the viscosity Ī· YX2 (C) suggests the dominance of the inter-ion repulsion.Submitted/Accepted versionFinancial support received from Natural Science Foundation of China (Nos. 11872052(YL); 21875024(CQ)), and the Science Challenge Project (No. TZ2016001) of China are acknowledged
Rapid reconstitution of ubiquitinated nucleosome using a non-denatured histone octamer ubiquitylation approach
Abstract Background Histone ubiquitination modification is emerging as a critical epigenetic mechanism involved in a range of biological processes. In vitro reconstitution of ubiquitinated nucleosomes is pivotal for elucidating the influence of histone ubiquitination on chromatin dynamics. Results In this study, we introduce a Non-Denatured Histone Octamer Ubiquitylation (NDHOU) approach for generating ubiquitin or ubiquitin-like modified histone octamers. The method entails the co-expression and purification of histone octamers, followed by their chemical cross-linking to ubiquitin using 1,3-dibromoacetone. We demonstrate that nucleosomes reconstituted with these octamers display a high degree of homogeneity, rendering them highly compatible with in vitro biochemical assays. These ubiquitinated nucleosomes mimic physiological substrates in function and structure. Additionally, we have extended this method to cross-linking various histone octamers and three types of ubiquitin-like proteins. Conclusions Overall, our findings offer an efficient strategy for producing ubiquitinated nucleosomes, advancing biochemical and biophysical studies in the field of chromatin biology
Rapid reconstitution of ubiquitinated nucleosome using a non-denatured histone octamer ubiquitylation approach.
BACKGROUND: Histone ubiquitination modification is emerging as a critical epigenetic mechanism involved in a range of biological processes. In vitro reconstitution of ubiquitinated nucleosomes is pivotal for elucidating the influence of histone ubiquitination on chromatin dynamics. RESULTS: In this study, we introduce a Non-Denatured Histone Octamer Ubiquitylation (NDHOU) approach for generating ubiquitin or ubiquitin-like modified histone octamers. The method entails the co-expression and purification of histone octamers, followed by their chemical cross-linking to ubiquitin using 1,3-dibromoacetone. We demonstrate that nucleosomes reconstituted with these octamers display a high degree of homogeneity, rendering them highly compatible with in vitro biochemical assays. These ubiquitinated nucleosomes mimic physiological substrates in function and structure. Additionally, we have extended this method to cross-linking various histone octamers and three types of ubiquitin-like proteins. CONCLUSIONS: Overall, our findings offer an efficient strategy for producing ubiquitinated nucleosomes, advancing biochemical and biophysical studies in the field of chromatin biology