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Jun Yoshida

Publications and source records attributed to Jun Yoshida.

At least 19 recordsLinked to original sources

Remark on twists of Frobenius algebra and link homology

We discuss twists on Frobenius algebras in the context of link homology. In his paper in 2006, Khovanov asserted that a twist of a Frobenius algebra yields an isomorphic chain complex on each link diagram. Although the result has been widely accepted for nearly two decades, a subtle gap in the original proof was found in the induction step of the construction of the isomorphism. Following discussion with Khovanov, we decided to provide a new proof. Our proof is based on a detailed analysis of configurations of circles in each state.

math.QA

Tailored ordering enables high-capacity cathode materials

Newly designed Li-ion battery cathode materials with high capacity and greater flexibility in chemical composition will be critical for the growing electric vehicles market. Cathode structures with cation disorder were once considered suboptimal, but recent demonstrations have highlighted their potential in Li$_{1+x}$M$_{1-x}$O$_{2}$ chemistries with a wide range of metal combinations M. By relaxing the strict requirements of maintaining ordered Li diffusion pathways, countless multi-metal compositions in LiMO$_2$ may become viable, aiding the quest for high-capacity cobalt-free cathodes. A challenge presented by this freedom in composition space is designing compositions which possess specific, tailored types of both long- and short-range orderings, which can ensure both phase stability and Li diffusion. However, the combinatorial complexity associated with local cation environments impedes the development of general design guidelines for favorable orderings. Here we propose ordering design frameworks from computational ordering descriptors, which in tandem with low-cost heuristics and elemental statistics can be used to simultaneously achieve compositions that possess favorable phase stability as well as configurations amenable to Li diffusion. Utilizing this computational framework, validated through multiple successful synthesis and characterization experiments, we not only demonstrate the design of LiCr$_{0.75}$Fe$_{0.25}$O$_2$, showcasing initial charge capacity of 234 mAhg$^{-1}$ and 320 mAhg$^{-1}$ in its 20% Li-excess variant Li$_{1.2}$Cr$_{0.6}$Fe$_{0.2}$O$_2$, but also present the elemental ordering statistics for 32 elements, informed by one of the most extensive first-principles studies of ordering tendencies known to us.

cond-mat.mtrl-sci

Development of an automatic modification system for generated programs using ChatGPT

In recent years, the field of artificial intelligence has been rapidly developing. Among them, OpenAI's ChatGPT excels at natural language processing tasks and can also generate source code. However, the generated code often has problems with consistency and program rules. Therefore, in this research, we developed a system that tests the code generated by ChatGPT, automatically corrects it if it is inappropriate, and presents the appropriate code to the user. This study aims to address the challenge of reducing the manual effort required for the human feedback and modification process for generated code. When we ran the system, we were able to automatically modify the code as intended.

cs.SE

Decomposition of the first Vassiliev derivative of Khovanov homology and its application

Khovanov homology extends to singular links via a categorified analogue of Vassiliev skein relation. In view of Vassiliev theory, the extended Khovanov homology can be seen as Vassiliev derivatives of Khovanov homology. In this paper, we develop a new method to compute the first derivative. Namely, we introduce a complex, called a crux complex, and prove that the Khovanov homologies of singular links with unique double points are homotopic to cofibers of endomorphisms on crux complexes. Since crux complexes are actually small for some links, the result enables a direct computation of the first derivative of Khovanov homology. Furthermore, it together with a categorified Vassiliev skein relation provides a brand-new method for the computation of Khovanov homology. In fact, we apply the result to determine the Khovanov complexes of all twist knots in a universal way.

math.GT

A cobordism realizing crossing change on $\mathfrak{sl}_2$ tangle homology and a categorified Vassiliev skein relation

In this paper, we discuss degree 0 crossing change on Khovanov homology in terms of cobordisms. Namely, using Bar-Natan's formalism of Khovanov homology, we introduce a sum of cobordisms that yields a morphism on complexes of two diagrams of crossing change, which we call the "genus-one morphism." It is proved that the morphism is invariant under the moves of double points in tangle diagrams. As a consequence, in the spirit of Vassiliev theory, taking iterated mapping cones, we obtain an invariant for singular tangles that extending sl(2) tangle homology; examples include Lee homology, Bar-Natan homology, and Naot's universal Khovanov homology as well as Khovanov homology with arbitrary coefficients. We also verify that the invariant satisfies categorified analogues of Vassiliev skein relation and the FI relation.

math.GT

Crossing change on Khovanov homology and a categorified Vassiliev skein relation

Khovanov homology is a categorification of the Jones polynomial, so it may be seen as a kind of quantum invariant of knots and links. Although polynomial quantum invariants are deeply involved with Vassiliev (aka. finite type) invariants, the relation remains unclear in case of Khovanov homology. Aiming at it, in this paper, we discuss a categorified version of Vassiliev skein relation on Khovanov homology. More precisely, we will show that the "genus-one" operation gives rise to a crossing change on Khovanov complexes. Invariance under Reidemeister moves turns out, and it enables us to extend Khovanov homology to singular links. We then see that a long exact sequence of Khovanov homology groups categorifies Vassiliev skein relation for the Jones polynomials. In particular, the Jones polynomial is recovered even for singular links. We in addition discuss the FI relation on Khovanov homology.

math.GT

Quantitative analysis of $p$-wave three-body losses via cascade process

We describe the three-body loss coefficient of identical fermions with $p$-wave interactions using a set of rate equations in which three-body recombination happens via an indirect process. Our theoretical treatment explains experimental results just above the universal scaling law regime of weak interactions. Furthermore, we theoretically extend and experimentally verify the rate equation model for the case of atoms trapped in two dimensions. Moreover, we find that the three-body loss coefficient in a two-dimensional trap is proportional to $A_{p}^{3}$ in the weakly interacting regime, where $A_{p}$ is the scattering area. Our results are useful in understanding three-body physics with $p$-wave interactions.

cond-mat.quant-gas

Unitarity-limited behavior of three-body collisions in a p-wave interacting Fermi gas

We experimentally investigate the unitarity-limited behavior of the three-body loss near a p-wave Feshbach resonance in a single-component Fermi gas of $^6$Li atoms. At the unitarity limit, the three-body loss coefficient $L_{3}$ exhibits universality in the sense that it is independent of the interaction strength and follows the predicted temperature scaling law of $L_3 \propto T^{-2}$. When decreasing the interaction strength from the unitarity regime, the three-body loss coefficient as a function of the interaction strength and temperature can be described by the theory based on the association of an excited resonant quasibound state and its relaxation into a deep stable dimer by collision with a third atom in the framework of the standard Breit-Wigner theoretical approach. The results reported here are important to understand the properties of a resonant p-wave Fermi gas in the prospect of quantum few- and many-body physics.

cond-mat.quant-gas

Categories of operators and actions of group operads

We propose a new model for multicategories with symmetries with respect to Zhang's group operads. The fully faithful embedding of the category of group operads into that of crossed interval groups is made use of, and it is shown that every multicategory gives rise to a fibration, in a sense, over a quotient of the total category of group operads. The symmetric structures can be presented as structures of internal presheaves over a category internal to the category of small categories, in other words a double category.

math.CT

Group operads as crossed interval groups

The goal of the paper is to establish and to investigate a fully faithful embedding of the category of group operads into that of crossed interval groups. For this, we introduce a monoidal structure on the slice of the category of operads over the operad of symmetric groups. Comparing with the monoidal structure on the category of interval sets discussed in the author's previous work, we obtain a monoidal functor connecting these two categories. It will be shown that this actually induces a fully faithful functor on monoid objects and does not change the underlying sets, so we obtain a required embedding. The conditions for crossed interval groups to belong to the essential image will be proposed; namely in terms of commutativity of certain elements. As a result, it will turn out that the group operads form a reflective subcategory of the category of crossed interval groups. Finally, we will discuss monoid objects in symmetric monoidal category and Hochschild homologies on them.

math.CT

Scaling Law for Three-body Collisions in Identical Fermions with $p$-wave Interactions

We experimentally confirmed the threshold behavior and scattering length scaling law of the three-body loss coefficients in an ultracold spin-polarized gas of $^6$Li atoms near a $p$-wave Feshbach resonance. We measured the three-body loss coefficients as functions of temperature and scattering volume, and found that the threshold law and the scattering length scaling law hold in limited temperature and magnetic field regions. We also found that the breakdown of the scaling laws is due to the emergence of the effective-range term. This work is an important first step toward full understanding of the loss of identical fermions with $p$-wave interactions.

cond-mat.quant-gas

Limits and colimits of crossed groups

Although the notion of crossed groups was originally introduced only in the simplicial case, the definition makes sense in the other categories. For instance, Batanin and Markl studied crossed interval groups to investigate symmetries on the Hochschild cohomology in view of operads. The aim of this paper is to make a comprehensive understanding of crossed groups for arbitrary base categories. In particular, we focus on the local presentability of the category of crossed groups, monadicity, and the basechange theorem along certain sorts of functors. The paper also contains the classification of crossed interval groups, which Batanin and Markl concerned about.

math.CT

Two-body relaxation in a Fermi gas at a p-wave Feshbach resonance

We systematically studied the two-body loss in a two-component Fermi gas of $^6$Li atoms near a p-wave Feshbach resonance. The two-body loss rate constants were measured for various temperatures and magnetic fields using atoms trapped in three-dimensional and quasi-two-dimensional traps. Our results were nicely reproduced by a theoretical model that incorporates the two-body loss as an imaginary part to the inverse of the scattering volume in the scattering amplitude expression. The observed loss suppression in quasi-two-dimensional traps may provide a promising strategy to realize a p-wave superfluid in a system of ultracold atoms.

cond-mat.quant-gas

Transversality theorem in highly relative situations and its application

In this paper, we aim to provide a notion of "relative objects", i.e. objects equipped with some sort of subobjects, in differential topology. In spite of active researches relating them, e.g. knot theory or the theory of manifolds with corners, there seem to be poor general notions to deal with them. Moreover, we want even more direct differential calculus on relative objects and extension of classical notions and theories to relative situations; e.g. functions, vector fields, jet bundles, singularities, and so on. To establish this, the notion of arrangements of manifolds is introduced, which, for example, enables us to control behaviors of smooth maps on manifolds around corners. We construct jet bundles and prove a relative version of Transversality Theorem for some sorts of arrangements. Finally, embedding theorem of manifolds with faces into polyhedra is proved as an application.

math.GT

Creation of p-wave Feshbach molecules in the selected angular momentum states using an optical lattice

We selectively create p-wave Feshbach molecules in the $m_{l}=\pm 1$ orbital angular momentum projection state of $^{6}$Li. We use an optical lattice potential to restrict the relative momentum of the atoms such that only the $m_{l}=\pm 1$ molecular state couples to the atoms at the Feshbach resonance. We observe the hollow-centered dissociation profile, which is a clear indication of the selective creation of p-wave molecules in the $m_{l}=\pm1$ states. We also measure the dissociation energy of the p-wave molecules created in the optical lattice and develop a theoretical formulation to explain the dissociation energy as a function of the magnetic field ramp rate for dissociation. The capability of selecting one of the two closely-residing p-wave Feshbach resonances is useful for the precise characterization of the p-wave Feshbach resonances.

cond-mat.quant-gas

A general method to construct cube-like categories and applications to homotopy theory

In this paper, we introduce a method to construct new categories which look like "cubes", and discuss model structures on the presheaf categories over them. First, we introduce a notion of thin-powered structure on small categories, which provides a generalized notion of "power-sets" on categories. Next, we see that if a small category $\mathcal{R}$ admits a good thin-powered structure, we can construct a new category $\square(\mathcal{R})$ called the cubicalization of the category. We also see that $\square(\mathcal{R})$ is equipped with enough structures so that many arguments made for the classical cube category $\square$ are also available. In particular, it is a test category in the sense of Grothendieck. The resulting categories contain the cube category $\square$, the cube category with connections $\square^c$, the extended cubical category $\square_Σ$ introduced by Isaacson, and cube categories $\square_G$ symmetrized by more general group operads $G$. We finally discuss model structures on the presheaf categories $\square(\mathcal{R})^\wedge$ over cubicalizations. We prove that $\square(\mathcal{R})^\wedge$ admits a model structure such that the simplicial realization $\square(\mathcal{R})^\wedge\to SSet$ is a left Quillen functor. Moreover, in the case of $\square_G$ for group operads $G$, $\square^\wedge_G$ is a monoidal model category, and we have a sequence of monoidal Quillen equivalences $\square Set \to \square_G^\wedge\to SSet$. For example, if $G=B$ is the group operad consisting of braid groups, the category $\square^\wedge_B$ is a braided monoidal model category whose homotopy category is equivalent to that of $SSet$.

math.CT

Hysteresis in quantized vortex shedding

It is shown using numerical simulations that flow patterns around an obstacle potential moving in a superfluid exhibit hysteresis. In a certain velocity region, there is a bistability between stationary laminar flow and periodic vortex shedding. The bistability exists in two and three dimensional systems.

cond-mat.quant-gas