1,478 research outputs found
Luttinger-volume violating Fermi liquid in the pseudogap phase of the cuprate superconductors
Based on the NMR measurements on BiSrLaCuO
(La-Bi2201) in strong magnetic fields, we identify the non-superconducting
pseudogap phase in the cuprates as a Luttinger-volume violating Fermi liquid
(LvvFL). This state is a zero temperature quantum liquid that does not break
translational symmetry, and yet, the Fermi surface encloses a volume smaller
than the large one given by the Luttinger theorem. The particle number enclosed
by the small Fermi surface in the LvvFL equals the doping level , not the
total electron number . Both the phase string theory and the dopon
theory are introduced to describe the LvvFL. For the dopon theory, we can
obtain a semi-quantitative agreement with the NMR experiments.Comment: The final version in PR
CP Violation for B
In the QCD factorization (QCDF) approach we study the direct CP violation in B-0→ρ0(ω)ρ0(ω)→π+π-π+π- via the ρ-ω mixing mechanism. We find that the CP violation can be enhanced by double ρ-ω mixing when the masses of the π+π- pairs are in the vicinity of the ω resonance, and the maximum CP violation can reach 28%. We also compare the results from the naive factorization and the QCD factorization
Radiative decays of the heavy-quark-spin molecular partner of
With the assumptions that the discovered at LHCb is a
hadronic molecule, using a nonrelativistic effective field theory we calculate
the radiative partial widths of with being
a shallow bound state and the heavy-quark-spin partner of
. The rescattering effect with the pole is
taken into account. The results show that the isoscalar
rescattering can increase the tree-level decay width of by about , while decrease that of
by a similar amount. The two-body
partial decay widths of the into and
are also calculated, and the results are about and
, respectively. Considering that the needs to be
reconstructed from the or final state in an experimental
measurement, the four-body partial widths of the into
and are explicitly calculated, and we find that
the interference effect between different intermediate states is
small. The total radiative decay width of the is predicted to be
about . Adding the hadronic decay widths of , the total width of the is finally predicted to be
keV.Comment: 27 pages, 13 figures. arXiv admin note: text overlap with
arXiv:2211.0247
Design of variable screw pitch rib snapping roller and residue cutter for corn harvesters
The blocking between two snapping rollers will seriously constrict the harvesting efficiency for corn harvester. A variable screw pitch rib snapping roller was developed to solve this problem. The comparative experiment between fixed screw pitch rib snapping rollers and variable screw pitch rib snapping rollers illustrated that variable screw pitch ribs can avoid corn-stalk blocking effectively, and it can improve working efficiency by 56.7%. Conservation tillage with standing corn residue was testified that it had a strong control of soil wind erosion. In order to implement this mode of conservation tillage at a production scale, a cutter was developed in this study. Subsequently, two experiments were conducted, one was to test the cutting ratio (defined as the totally cut off stalk population divided by total stalk population), and the other one was to test standing-residue height
Impact of residual and intrafractional errors on strategy of correction for image-guided accelerated partial breast irradiation
<p>Abstract</p> <p>Background</p> <p>The cone beam CT (CBCT) guided radiation can reduce the systematic and random setup errors as compared to the skin-mark setup. However, the residual and intrafractional (RAIF) errors are still unknown. The purpose of this paper is to investigate the magnitude of RAIF errors and correction action levels needed in cone beam computed tomography (CBCT) guided accelerated partial breast irradiation (APBI).</p> <p>Methods</p> <p>Ten patients were enrolled in the prospective study of CBCT guided APBI. The postoperative tumor bed was irradiated with 38.5 Gy in 10 fractions over 5 days. Two cone-beam CT data sets were obtained with one before and one after the treatment delivery. The CBCT images were registered online to the planning CT images using the automatic algorithm followed by a fine manual adjustment. An action level of 3 mm, meaning that corrections were performed for translations exceeding 3 mm, was implemented in clinical treatments. Based on the acquired data, different correction action levels were simulated, and random RAIF errors, systematic RAIF errors and related margins before and after the treatments were determined for varying correction action levels.</p> <p>Results</p> <p>A total of 75 pairs of CBCT data sets were analyzed. The systematic and random setup errors based on skin-mark setup prior to treatment delivery were 2.1 mm and 1.8 mm in the lateral (LR), 3.1 mm and 2.3 mm in the superior-inferior (SI), and 2.3 mm and 2.0 mm in the anterior-posterior (AP) directions. With the 3 mm correction action level, the systematic and random RAIF errors were 2.5 mm and 2.3 mm in the LR direction, 2.3 mm and 2.3 mm in the SI direction, and 2.3 mm and 2.2 mm in the AP direction after treatments delivery. Accordingly, the margins for correction action levels of 3 mm, 4 mm, 5 mm, 6 mm and no correction were 7.9 mm, 8.0 mm, 8.0 mm, 7.9 mm and 8.0 mm in the LR direction; 6.4 mm, 7.1 mm, 7.9 mm, 9.2 mm and 10.5 mm in the SI direction; 7.6 mm, 7.9 mm, 9.4 mm, 10.1 mm and 12.7 mm in the AP direction, respectively.</p> <p>Conclusions</p> <p>Residual and intrafractional errors can significantly affect the accuracy of image-guided APBI with nonplanar 3DCRT techniques. If a 10-mm CTV-PTV margin is applied, a correction action level of 5 mm or less is necessary so as to maintain the RAIF errors within 10 mm for more than 95% of fractions. Pre-treatment CBCT guidance is not a guarantee for safe delivery of the treatment despite its known benefits of reducing the initial setup errors. A patient position verification and correction during the treatment may be a method for the safe delivery.</p
Coherent phonon dynamics in spatially separated graphene mechanical resonators
Vibrational modes in mechanical resonators provide a promising candidate to
interface and manipulate classical and quantum information. The observation of
coherent dynamics between distant mechanical resonators can be a key step
towards scalable phonon-based applications. Here we report tunable coherent
phonon dynamics with an architecture comprising three graphene mechanical
resonators coupled in series, where all resonators can be manipulated by
electrical signals on control gates. We demonstrate coherent Rabi oscillations
between spatially separated resonators indirectly coupled via an intermediate
resonator serving as a phonon cavity. The Rabi frequency fits well with the
microwave burst power on the control gate. We also observe Ramsey interference,
where the oscillation frequency corresponds to the indirect coupling strength
between these resonators. Such coherent processes indicate that information
encoded in vibrational modes can be transferred and stored between spatially
separated resonators, which can open the venue of on-demand phonon-based
information processing
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