arXiv subjects

Sachin Chauhan

Publications and source records attributed to Sachin Chauhan.

7 recordsLinked to original sources

arXiv2026

Open strings on knot complements

Using skein valued holomorphic curve counting techniques, we give a flow loop formula for the skein valued partition function of the Lagrangian knot complement of a fibered knot (of the $A$-model open topological strings with Lagrangian $A$-branes wrapping the complement) in the cotangent bundle of the three-sphere and in the resolved conifold. For torus knots we show that the partition function in the cotangent bundle localizes on two or three holomorphic annuli and give a corresponding generalized quiver structure for the partition function in the resolved conifold. We connect the formula to the augmentation curve, the representation variety of the knot contact homology algebra of the knot, generated by Reeb chords of its Legendrian conormal and with differential given by holomorphic disks interpolating between words of Reeb chords. The curve admits a quantization as a $q$-difference equation for the generating function of symmetrically colored HOMFLYPT-polynomials of the knot or, geometrically, for the $U(1)$-partition function of the knot conormal. For $(2,2p+1)$-torus knots we show that, after a change of variables, the partition function of the knot complement also satisfies this $q$-difference equation. This gives another geometrically defined coordinate chart for the $D$-module defined by the quantized augmentation polynomial.

hep-th↗

arXiv2025

Full twists and stability of knots and quivers

We relate the stability of knot invariants under twisting a pair of strands to the stability of symmetric quivers under unlinking (or linking) operation. Starting from the HOMFLY-PT skein relations, we confirm the stable growth of $Sym^r$-coloured HOMFLY-PT polynomials under the addition of a~full twist to the knot. On the other hand, we show that symmetric quivers exhibit analogous stable growth under unlinking or linking of the quiver augmented with the extra node; in some cases this augmented quiver captures the spectrum of motivic Donaldson-Thomas invariants of all quivers in the sequence. Combining these two versions of the stable growth, we conjecture that performing a~full twist on any knot corresponds to appropriate unlinking or linking of the corresponding augmented quiver -- this statement is an important step towards a~direct definition of the knot-quiver correspondence based on the knot diagram. We confirm the conjecture for all twist knots, $(2,2p+1)$ torus knots, and all pretzel knots up to 15 crossings with an~odd number of twists in each twist region.

hep-th↗

arXiv2025

Self-Regulating Cars: Automating Traffic Control in Free Flow Road Networks

Free-flow road networks, such as suburban highways, are increasingly experiencing traffic congestion due to growing commuter inflow and limited infrastructure. Traditional control mechanisms, such as traffic signals or local heuristics, are ineffective or infeasible in these high-speed, signal-free environments. We introduce self-regulating cars, a reinforcement learning-based traffic control protocol that dynamically modulates vehicle speeds to optimize throughput and prevent congestion, without requiring new physical infrastructure. Our approach integrates classical traffic flow theory, gap acceptance models, and microscopic simulation into a physics-informed RL framework. By abstracting roads into super-segments, the agent captures emergent flow dynamics and learns robust speed modulation policies from instantaneous traffic observations. Evaluated in the high-fidelity PTV Vissim simulator on a real-world highway network, our method improves total throughput by 5%, reduces average delay by 13%, and decreases total stops by 3% compared to the no-control setting. It also achieves smoother, congestion-resistant flow while generalizing across varied traffic patterns, demonstrating its potential for scalable, ML-driven traffic management.

cs.LG↗

arXiv2024

$q$-Series Invariants of Three-Manifolds and Knots-Quivers Correspondence

The Gukov-Pei-Putrov-Vafa (GPPV) conjecture is a relationship between two three-manifold invariants: the Witten-Reshetikhin-Turaev (WRT) invariant and the $\widehat{Z}$ (``Z-hat'') invariant. In fact, WRT invariant is defined at roots of unity, $\mathbbm{q}\left(\exp\left(\frac{2πi}{k+2}\right),~k\in\mathbb{Z}_+,~\text{for}~SU(2)\right)$, and is generally a complex number, whereas $\widehat{Z}$-invariant is a $q$-series with integer coefficients such that $|q|<1$. Therefore, $\widehat{Z}$-invariant can be obtained from WRT-invariant by performing a particular analytic continuation, $\mathbbm{q}\rightarrow q$. In this thesis, we first examine this conjecture for $SO(3)$ and the ortho-symplectic supergroup $OSp(1|2)$. This is done by setting up the WRT invariant for the respective groups and then performing the particular analytic continuation to extract $\widehat{Z}$. As a result of this exercise, we found that $\widehat{Z}^{SU(2)}=\widehat{Z}^{SO(3)}$ and identified a relation between $\widehat{Z}^{SU(2)}$ and $\widehat{Z}^{OSp(1|2)}$. Motivated by the equality of $\widehat{Z}$ for $SU(2)$ and $SO(3)$ groups, we study this conjecture for $SU(N)/\mathbb{Z}_m$ groups, where $\mathbb{Z}_m$ is a subgroup of $\mathbb{Z}_N$, in our second paper. We subsequently found that $\widehat{Z}^{SU(N)/\mathbb{Z}_m}=\widehat{Z}^{SU(N)}$. Another theme of the thesis is to study a conjecture between knot theory and quiver representation theory. More precisely, this conjecture relates the generating function of the symmetric $r$-colored HOMFLY-PT polynomial with the motivic generating series associated with a symmetric quiver. In particular, we obtain a quiver representation for a family of knots called double twist knots $K(p,-m)$. Primarily, we exploit the reverse engineering of Melvin-Morton-Rozansky (MMR) formalism to deduce the pattern of the matrix for these quivers.

math-ph↗

arXiv2024

Knot-Quiver correspondence for double twist knots

We obtain a quiver representation for a family of knots called double twist knots $K(p,-m)$. Particularly, we exploit the reverse engineering of Melvin-Morton-Rozansky(MMR) formalism to deduce the pattern of the charge matrix for these quivers.

hep-th↗

arXiv2023

Gukov-Pei-Putrov-Vafa conjecture for $SU(N)/\mathbb{Z}_m$

In our earlier work, we studied the $\hat{Z}$-invariant(or homological blocks) for $SO(3)$ gauge group and we found it to be same as $\hat{Z}^{SU(2)}$. This motivated us to study the $\hat{Z}$-invariant for quotient groups $SU(N)/\mathbb{Z}_m$, where $m$ is some divisor of $N$. Interestingly, we find that $\hat{Z}$-invariant is independent of $m$.

hep-th↗

arXiv2023

$\hat Z$- invariant for $SO(3)$ and $OSp(1|2)$ Groups

Three-manifold invariants $\hat Z$ (''$Z$-hat''), also known as homological blocks, are $q$-series with integer coefficients. Explicit $q$-series form for $\hat Z$ is known for $SU(2)$ group, supergroup $SU(2|1)$ and ortho-symplectic supergroup $OSp(2|2)$. We focus on $\hat Z$ for $SO(3)$ group and orthosymplectic supergroup $OSp(1|2)$ in this paper. Particularly, the change of variable relating $SU(2)$ link invariants to the $SO(3)$ & $OSp(1|2)$ link invariants plays a crucial role in explicitly writing the $q$-series.

hep-th↗