Searcharxiv⌕ Search

arXiv subjects

Qian Kong

Publications and source records attributed to Qian Kong.

7 recordsLinked to original sources
arXiv2026

Shortcuts to adiabaticity for rapid soliton compression in nonlocal media

We investigate shortcut-to-adiabaticity protocols for the rapid compression of optical solitons in nonlocal media. Using a variational approximation, we derive an effective Ermakov-like equation for the soliton width and employ inverse engineering to design propagation-dependent control parameters. Three control strategies are compared, based respectively on modulation of the characteristic nonlocal length, the Kerr nonlinearity, and the external parabolic confinement. We show that all three protocols enable high-fidelity compression over strongly reduced propagation distances. By comparing control smoothness and final fidelity, we find that the relative performance of the protocols in the very short-distance regime depends on the chosen criterion, revealing a trade-off between implementation smoothness and target-profile accuracy. These results establish a practical and general route to fast soliton manipulation in nonlocal media.

physics.optics↗
arXiv2026

Fast compression of pure-quartic solitons in nonlinear optical fibers via shortcuts to adiabaticity

Pure-quartic solitons (PQSs) supported by negative fourth-order dispersion have recently attracted considerable interest. In this work, we study both adiabatic and nonadiabatic compression of PQSs in nonlinear optical fibers with pure quartic dispersion in the presence of distributed gain and loss. Within a variational framework, we show that, for weak constant gain, the adiabatic compression dynamics can be mapped onto the motion of an effective particle in a slowly deformed potential, providing an intuitive physical picture. To overcome the long propagation distance required by conventional adiabatic condition, we exploit shortcuts to adiabaticity (STA) based on inverse engineering and derive analytical gain-loss profiles, with appropriate boundary conditions that realize a prescribed fast compression over a shorter propagation distance. Numerical simulations confirm the theoretical predictions and indicate a minimum propagation distance below which noticeable waveform distortion emerges. Compared with standard adiabatic references, the STA design significantly reduces the required compression distance while maintaining high-fidelity PQS evolution.

physics.optics↗
arXiv2022

Efficient broadband frequency conversion via shortcut to adiabaticity

The method of adiabatic frequency conversion, in analogy with the two level atomic system, has been put forward recently and verified experimentally to achieve robust frequency mixing processes such as sum and difference frequency generation. Here we present a comparative study of efficient frequency mixing using various techniques of shortcuts to adiabaticity (STA) such as counter-diabatic driving and invariant-based inverse engineering. We show that, it is possible to perform sum frequency generation by properly designing the poling structure of a periodically poled crystal and the coupling between the input lights and the crystal. The required crystal length for frequency conversion is significantly decreases beyond the adiabatic limit. Our approach significantly improves the robustness of the process against the variation in temperature as well as the signal frequency. By introducing a single parameter control technique with constant coupling and combining with the inverse engineering, perturbation theory and optimal control, we show that the phase mismatch can be further optimized with respect to the fluctuations of input wavelength and crystal temperature that results into a novel experimentally realizable mixing scheme.

quant-ph↗
arXiv2011

Terwilliger algebra of Odd graphs

In [The Terwilliger algebra of the Johnson schemes, Discrete Mathematics 307 (2007) 1621--1635], Levstein and Maldonado computed the Terwilliger algebra of the Johnson scheme $J(n,m)$ when $3m\leq n$. The distance-$m$ graph of $J(2m+1,m)$ is the Odd graph $O_{m+1}$. In this paper, we determine the Terwilliger algebra of $O_{m+1}$ and give its basis.

math.CO↗
arXiv2011

The Terwilliger algebra of the incidence graphs of Johnson geometry

Levstein and Maldonado [F. Levstein, C. Maldonado, The Terwilliger algebra of the Johnson schemes, Discrete Mathematics 307 (2007) 1621--1635] computed the Terwilliger algebra of the Johnson scheme $J(n,m)$ when $3m\leq n$. In this paper, we determine the Terwilliger algebra of the incidence graph $J(n,m,m+1)$ of Johnson geometry when $3m\leq n$, give two bases of this algebra, and calculate its dimension.

math.CO↗
arXiv2010

Analytical theory of dark nonlocal solitons

We investigate properties of dark solitons in nonlocal materials with an arbitrary degree of nonlocality. We employ the variational technique and describe the dark solitons, for the first time, in the whole range of degree of nonlocality.

nlin.PS↗