3,961 research outputs found
Stark many-body localization with long-range interactions
In one-dimensional (1D) disorder-free interacting systems, a sufficiently
strong linear potential can induce localization of the many-body eigenstates, a
phenomenon dubbed as Stark many-body localization (MBL). In this paper, we
investigate the fate of Stark MBL in 1D spinless fermions systems with
long-range interactions, specifically focusing on the role of interaction
strength. We obtain the Stark MBL phase diagrams by computing the mean gap
ratio and many-body inverse participation ratio at half-filling. We show that,
for short-range interactions, there is a qualitative symmetry between the
limits of weak and strong interactions. However, this symmetry is absent in the
case of long-range interactions, where the system is always Stark many-body
localized at strong interactions, regardless of the linear potential strength.
Furthermore, we study the dynamics of imbalance and entanglement with various
initial states using time-dependent variational principle (TDVP) numerical
methods. We reveal that the dynamical quantities display a strong dependence on
the initial conditions, which suggests that the Hilbert-space fragmentation
precludes thermalization. Our results demonstrate the robustness of Stark MBL
even in the presence of long-range interactions and offer an avenue to explore
MBL in disorder-free systems with long-range interactions
Short-range interaction of strongly nonlocal spatial optical solitons
A novel phenomenon is discovered that the short-range interaction between
strongly nonlocal spatial solitons depends sinusoidally on their phase
difference. The two neighbouring solitons at close proximate can be
inter-trapped via the strong nonlocality, and propagate together as a whole.
The trajectory of the propagation is a straight line with its slope controlled
by the phase difference. The experimental results carried out in nematic liquid
crystals agree quantitatively with the prediction. Our study suggests that the
phenomenon to steer optical beams by controlling the phase difference could be
used in all-optical information processing.Comment: 4 pages 6 figure
Regularized Shallow Image Prior for Electrical Impedance Tomography
Untrained Neural Network Prior (UNNP) based algorithms have gained increasing
popularity in tomographic imaging, as they offer superior performance compared
to hand-crafted priors and do not require training. UNNP-based methods usually
rely on deep architectures which are known for their excellent feature
extraction ability compared to shallow ones. Contrary to common UNNP-based
approaches, we propose a regularized shallow image prior method that combines
UNNP with hand-crafted prior for Electrical Impedance Tomography (EIT). Our
approach employs a 3-layer Multi-Layer Perceptron (MLP) as the UNNP in
regularizing 2D and 3D EIT inversion. We demonstrate the influence of two
typical hand-crafted regularizations when representing the conductivity
distribution with shallow MLPs. We show considerably improved EIT image quality
compared to conventional regularization algorithms, especially in structure
preservation. The results suggest that combining the shallow image prior and
the hand-crafted regularization can achieve similar performance to the Deep
Image Prior (DIP) but with less architectural dependency and complexity of the
neural network
Angular Reconstruction of a Lead Scintillating-Fiber Sandwiched Electromagnetic Calorimeter
A new method called Neighbor Cell Deposited Energy Ratio (NCDER) is proposed
to reconstruct incidence position in a single layer for a 3-dimensional imaging
electromagnetic calorimeter (ECAL).This method was applied to reconstruct the
ECAL test beam data for the Alpha Magnetic Spectrometer-02 (AMS-02). The
results show that this method can achieve an angular resolution of 7.36\pm 0.08
/ \sqrt(E) \oplus 0.28 \pm 0.02 degree in the determination of the photons
direction, which is much more precise than that obtained with the
commonly-adopted Center of Gravity(COG) method (8.4 \pm 0.1 /sqrt(E) \oplus
0.8\pm0.3 degree). Furthermore, since it uses only the properties of
electromagnetic showers, this new method could also be used for other type of
fine grain sampling calorimeters.Comment: 6 pages, 8 figure
Online scheduling on three uniform machines
AbstractThis paper investigates the online scheduling on three uniform machines problem. Denote by sj the speed of each machine, j=1,2,3. Assume 0<s1≤s2≤s3, and let s=s2/s1 and t=s3/s2 be two speed ratios. We show the greedy algorithm LS is an optimal online algorithm when the speed ratios (s,t)∈G1∪G2, where G1={(s,t)|1≤t<1+316,s≥3t5+2t−6t2} and G2={(s,t)|s(t−1)t≥1+s,s≥1,t≥1}. The competitive ratio of LS is 1+s+2sts+st when (s,t)∈G1 and 1+sst+1 when (s,t)∈G2. Moreover, for the general speed ratios, we show the competitive ratio of LS is no more than min{1+s+2sts+st,1+sst+1,1+s+3st1+s+st} and its overall competitive ratio is 2 which matches the overall lower bound of the problem
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