Kibble-Zurek scaling of the one-dimensional Bose-Hubbard model at finite temperatures

We use tensor network methods - Matrix Product States, Tree Tensor Networks, and Locally Purified Tensor Networks - to simulate the one dimensional Bose-Hubbard model for zero and finite temperatures in experimentally accessible regimes. We first explore the effect of thermal fluctuations on the system ground state by characterizing its Mott and superfluid features. Then, we study the behavior of the out-of-equilibrium dynamics induced by quenches of the hopping parameter. We confirm a Kibble-Zurek scaling for zero temperature and characterize the finite temperature behavior, which we explain by means of a simple argument.Comment: 13 pages, 12 figure

Comparison of real-time elastography and multiparametric MRI for prostate cancer detection: A whole-mount step-section analysis

OBJECTIVE. The purpose of this study was to compare prostate cancer detection rate of real-time elastography (RTE) with that of multiparametric MRI to evaluate the advantages and disadvantages of the two methods. SUBJECTS AND METHODS. Thirty-nine patients with biopsy-proven prostate cancer underwent both RTE and multiparametric MRI to localize prostate cancer before radical prostatectomy. RTE was performed to assess prostate tissue elasticity, and hard lesions were considered suspicious for prostate cancer. Multiparametric MRI included T2-weighted MRI, diffusion-weighted MRI (DWI), and contrast-enhanced MRI (CE-MRI) with an endorectal coil at 1.5 T. After radical prostatectomy, whole-mount step sections of the prostate were generated, and the prostate cancer detection rates with both modalities were analyzed for cancer lesions measuring 0.2 cm 3 or larger. RESULTS. Histopathologic examination revealed 61 cancer lesions. RTE depicted 39 of 50 cancer lesions (78.0%) in the peripheral zone and 2 of 11 (18.2%) in the transitional zone. Multiparametric MRI depicted 45 of 50 cancer lesions (90.0%) in the peripheral zone and 8 of 11 (72.7%) in the transitional zone. Significant differences between the two modalities were found for the transitional zone and anterior part in prostates with volumes greater than 40 cm3 (p \u3c 0.05). Detection rates for high-risk prostate cancer (Gleason score ≥ 4 and 3) and cancer lesions with volumes greater than 0.5 cm3 were high for both methods (93.8% and 80.5% for RTE, 87.5% and 92.7% for multiparametric MRI). Volumetric measurements of prostate cancer were more reliable with T2-weighted MRI than with RTE (Spearman rank correlation, 0.72 and 0.46). CONCLUSION. RTE and multiparametric MRI depicted high-risk prostate cancer with high sensitivity. However, multiparametric MRI seems to have advantages in tumor volume assessment and for the detection of prostate cancer in the transitional zone and anterior part within prostates larger than 40 cm3. American Roentgen Ray Society

A positive tensor network approach for simulating open quantum many-body systems

Open many-body quantum systems play an important role in quantum optics and condensed-matter physics, and capture phenomena like transport, interplay between Hamiltonian and incoherent dynamics, and topological order generated by dissipation. We introduce a versatile and practical method to numerically simulate one-dimensional open quantum many-body dynamics using tensor networks. It is based on representing mixed quantum states in a locally purified form, which guarantees that positivity is preserved at all times. Moreover, the approximation error is controlled with respect to the trace norm. Hence, this scheme overcomes various obstacles of the known numerical open-system evolution schemes. To exemplify the functioning of the approach, we study both stationary states and transient dissipative behaviour, for various open quantum systems ranging from few to many bodies.Comment: 13 pages, 7 figures, significant material on error bounds adde

Sonoelastography of the Common Flexor Tendon of the Elbow with Histologic Agreement: A Cadaveric Study.

Purpose To determine the correlation of the results of conventional B-mode ultrasonography (US) and compression sonoelastography with histologic results in common flexor tendons of the elbow in human cadavers. Materials and Methods Twenty-five common flexor tendons were evaluated in 16 fresh, unembalmed cadavers of 11 women with a median age of 85 years (range, 71-101 years) and five men with a median age of 78 years (range, 70-88 years). Informed consent was provided according to the last will of the donors. B-mode US results were classified as grade 1, normal tendon with homogeneous fibrillar pattern; grade 2, tendon thickening or hypoechoic areas and/or calcifications in less than 30% of the tendon; or grade 3, hypoechoic areas and/or calcifications greater than 30% of the tendon. Sonoelastographic results were grade 1, blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). The intraclass correlation coefficient was calculated to determine agreement with histologic findings for each B-mode US, sonoelastographic, and combined B-mode US and sonoelastographic examination. Histologic results were grade 1, normal, with parallel fibrillar pattern; grade 2, mild tendinopathy, with cellular infiltration, angiogenesis, or fatty vacuoles; or grade 3, severe tendinopathy, with loss of parallel collagen structure and necrosis. Results Histologic alterations were detected in 44% (11 of 25) of biopsy specimens. Intraclass correlation with histologic results was 0.57 for B-mode US, 0.68 for sonoelastography, and 0.84 for the combination of the two approaches. Conclusion The addition of sonoelastography to B-mode US provided statistically significant improvement in correlation with histologic results compared with the use of B-mode US alone (P \u3c .02). (©) RSNA, 2016 Online supplemental material is available for this article

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