Talks

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Cold-Atom Based Quantum Simulators and Forthcoming Quantum Technology Applications
Monday, 30 March 2026
Time Speaker Title Resources
09:00 to 09:40 Dan Stamper Kurn (University of California, Berkeley, USA) Cold-atom quantum simulation of geometric effects in materials

How do the intrinsic geometric properties of a material affect its extrinsic material properties? My research group is investigating aspects of this question through experimentation on atomic quantum gases. First, we are exploring how the geometry of energy bands dictates properties such as parallel transport through band structure and how a measure of the relative geometry of two bands — the interband Berry connection — is experimentally determined through the equivalent of optical spectroscopy. Second, we are exploring geometric frustration, particularly how it impacts the motion of itinerant particles, with a specific focus on the kagome lattice, into which we can now place both Bose and Fermi gases. Third, we are interested in how certain superfluids can acquire topological properties. I will describe how the ingredients of such topological superfluids might be realized in ultracold Fermi gases of titanium, and will present early-stage work on preparing such gases.
09:40 to 10:20 Ana Maria Rey (University of Colorado, Boulder, USA) Quantum Simulation of the Dicke Model in a Two-Dimensional Ion Crystal

In this talk I will report on the experimental realization of far-from-equilibrium dynamics of the Dicke model in a closed system of ~100 trapped ions arranged in a two-dimensional crystal. This highly controllable platform allows us to study how collective spins and vibrational motion interact across regimes ranging from simple and nearly integrable to strongly coupled and chaotic. We observe a dynamical phase transition, the onset of quantum chaos beyond mean-field descriptions, and the growth of quantum correlations associated with thermalization. We further infer quantum-fluctuation-driven spin squeezing below the standard quantum limit, followed by coherent collapses and revivals, demonstrating long-lived coherence in a strongly interacting many-body system.
10:50 to 11:30 Thomas Busch (Okinawa Institute of Science and Technology, Onna, Japan) Using Quantum Statistics to create Work: The Pauli Engine and Beyond

Heat engines convert thermal energy into mechanical work and have been extensively studied in the classical and quantum regimes. In the quantum domain, however, nonclassical forms of energy exist, which are distinct from traditional heat and which can also be harnessed to generate work in cyclic engine protocols.
 
This presentation will introduce the concept of the Pauli engine: a novel quantum many-body engine powered by the energy difference between fermionic and bosonic ultracold particle ensembles, arising from the Pauli exclusion principle. The distinct quantum statistics lead to a redistribution of population across energy levels, enabling engine cycles that replace traditional heat strokes in the quantum Otto cycle. This concept has recently been realized experimentally in the BEC-BCS crossover regime [1].

Building on this idea, we also present several concepts for hybrid quantum-classical engines, where a change in quantum statistics is implemented either during the adiabatic work strokes or the isochoric heat strokes [2]. While the Pauli engine alone demonstrated high efficiency, we show that combining quantum and classical effects can further enhance both efficiency and work output. All cycles are discussed in the context of ultracold atomic gases, which are well suited for their experimental realisation.

References:
 
[1] J. Koch, K. Menon, E. Cuestas, S. Barbosa, E. Lutz, T. Fogarty, Th. Busch, A. Widera, Nature 621, 723 (2023).
[2] K. Menon, Th. Busch, and T. Fogarty, Quantum Science and Technology 10, 045039 (2025)
11:30 to 12:10 Shovan Dutta (RRI Bengaluru, India) Long-range multipartite entanglement from local drive

I will talk about how one can use permutation symmetry and a local incoherent pump to generate W states of N distant qubits. The model consists of N identical spin-1/2 chains coupled to a central spin via an ancilla. Incoherently pumping the central qubit drives the system to an exactly solvable matrix product state of bond dimension 2, after which a global parity measurement projects the outermost qubits to a W state. For N=2 one gets a rainbow state. The protocol is based on fermonic quantum simulation with local operators on a star geometry. I will discuss how one may realize the required central coupling by Floquet engineering.
12:10 to 12:50 Manas Kulkarni (ICTS, Bengaluru, India) Extreme dynamics and relaxation in quantum matter

The evolution of quantum gases released from traps is studied through hydrodynamics, both analytically and numerically, in one and two dimensions [1]. We demonstrate long-time self-similar solutions of the Euler equations for density and velocity fields, deriving the associated scaling exponents and functions. The expanding gas develops a shock front, and the cloud size grows as a power law in time, with the exponent linked to the equation of state. We also examine relaxation dynamics in a trapped gas. This hydrodynamic framework provides a versatile tool for exploring very far-from-equilibrium collective phenomena of quantum matter. We will also present some preliminary results on time dynamics of classical Riesz gas both from a microscopic and a hydrodynamic perspective along with a recap of time evolution and thermalization in trapped classical hard rods [2].

[1] R. Mukherjee, A. Dhar, M. Kulkarni, S. S. Ray, arXiv:2509.00399
[2] D. Bagchi, J. Kethepalli, V. B. Bulchandani, A. Dhar, D. A. Huse, M. Kulkarni, A. Kundu, Phys. Rev. E 108, 064130 (2023)
14:30 to 15:10 Simon Lee Cornish (Durham University, Durham, UK) Ultracold RbCs molecules in magic-wavelength traps: a platform for quantum simulation

Ultracold polar molecules are an exciting platform for quantum science and technology. The combination of rich internal structure of vibration and rotation, controllable long-range dipolar interactions and strong coupling to applied electric and microwave fields has inspired many applications. These include quantum simulation of strongly interacting many-body systems, the study of quantum magnetism, quantum metrology and molecular clocks, quantum computation, precision tests of fundamental physics and the exploration of ultracold chemistry. Many of these applications require full quantum control of both the internal and motional degrees of freedom of the molecule at the single particle level, combined with traps that support long coherence times for rotational-state superpositions.

Using ultracold RbCs molecules assembled from ultracold atoms, we demonstrate all these requirements. We present a novel magic-wavelength trap that supports second-scale rotational coherences in a gas of molecules and gives access to controllable dipole-dipole interactions. We also report the efficient assembly of individual molecules in optical tweezers. By transferring the molecules into magic-wavelength tweezers, we demonstrate long-lived rotational coherences. In the magic-wavelength tweezers we can resolve Hertz-scale dipolar interactions between pairs of molecules. We then use the dipolar interaction to engineer entanglement, both using a spin-exchange protocol and by direct microwave excitation. Correcting for leakage errors, we measure an entanglement fidelity of 0.976 +/- 0.015.

Finally, as an outlook, we discuss progress towards a quantum gas microscope for ultracold molecules. We demonstrate in-situ detection of individual molecules in a thermal bulk gas by pinning in a deep 2D optical lattice prior to dissociation and detection. Further, by mapping two internal states of the molecule to different atomic species, we demonstrate simultaneous detection of the position and rotational state of individual molecules, paving the way to simulations of quantum magnetism with single-site and spin-resolved detection.
15:10 to 15:50 Sadiq Rangwala (Raman Research Institute, Bengaluru, India) Structural Transitions and Stochastic Dynamics in Trapped Ion Crystals

We present a new ion trap experiment, with an end cap type Paul trap built for precision spectroscopy and metrology [1,2]. We will discuss the performance of this experiment and then move quickly to the observation of three dimensional trapped ion crystals of Ca+ ions. The crystals form when the ions attain their configuration of minimum energy (CME) as a result of laser cooling of the ions. As the trap anisotropy is tuned, the crystals deform and structural transitions are seen. We study in detail three distinct structural transitions, all of which break symmetry with a change in the parity-odd octopole order parameter. Our observations show spontaneous symmetry breaking illustrated by a Higgs-like mode, dynamical catastrophe resulting in hysterisis, and stochastic switching [3].
In another experiment we study the thermal activation of the spontaneous inversion of a square pyramid ion crystal, which is aided by permutation symmetry and use this paradigm to test the multidimensional Kramers-Langer theory for reaction rates for the first time [4].

References
[1] A. Prakash, A. Ayyadevara, E. Krishnakumar, and S. A. Rangwala, Low divergence cold-wall oven for loading ion traps, Rev. Sci. Instrum. 95, 033202 (2024)
[2] AnandPrakash,AkhilAyyadevara,E.Krishnakumar, M. Ibrahim, K. M. Yatheendran, Subhadeep De, Sayan Patra, S. A. Rangwala, Endcap-Type Paul Trap for Precision Spectroscopy and Studies of Controlled Interactions, arXiv:2601.07328
[3] Akhil Ayyadevara, Anand Prakash, Shovan Dutta, Arun Paramekanti, and S. A. Rangwala, Observing the dynamics of octupolar structural transitions in trapped-ion clusters, arXiv:2505.16378v3 (Accepted PRR)
[4] Akhil Ayyadevara, Anand Prakash, Shovan Dutta, Arun Paramekanti, and S. A. Rangwala, Symmetry-controlled thermal activation in pyramidal Coulomb clusters: Testing Kramers-Langer theory, arXiv:2601.04883
15:50 to 16:10 Adarsh Prasad Raghuram (Durham University, Durham, UK) Synthetic dimensions with ultracold RbCs in a molecular microscope

An important advance in quantum simulation of many-body systems with ultracold atoms has been the development of quantum gas microscopes, with single particle detection and manipulation. Applying these techniques to ultracold molecules allows for the study of a wider variety of models, including anisotropic Hamiltonians and many-body phases due to the molecules’ rich internal structure and the long-range dipolar interactions [1]. Here, we demonstrate spin-resolved detection of single ultracold molecules in an optical lattice [2].
Synthetic dimensions involve using an internal degree of freedom of the system to simulate an extra spatial dimension. We use a stroboscopic microwave scheme to couple multiple rotational states of the molecule and realise a synthetic dimension within the internal structure of the molecules. Using only the different rotational states of the molecule, we prepare a one-dimensional synthetic lattice, realising the SSH (Su–Schrieffer–Heeger) model for up to 8 synthetic lattice sites. We probe the bulk states and edge states of the system as well as the topological phase transition described by the model. We utilise the long lifetimes and coherence times afforded to us by molecules to accurately measure the edge state energy splitting and show the topological protection of the edge states in this model.

[1] Cornish, S.L., Tarbutt, M.R. and Hazzard, K.R.A., Nature Physics 20(5), 730 (2024).
[2] J. M. Mortlock, A. P. Raghuram, B. P. Maddox, P. D. Gregory, and S. L. Cornish. arXiv:2506.12329v1 (2025)
[3] Sundar, B., Gadway, B. & Hazzard, K.R.A. Sci Rep 8, 3422 (2018).
16:30 to 17:30 Ana Maria Rey (University of Colorado, Boulder, USA) Optical lattice clocks: From Timekeepers to Spies of the Quantum Realm (CL-1)

Harnessing the behavior of complex systems is at the heart of quantum technologies. Precisely engineered ultracold gases are emerging as a powerful tool for this task. In this lecture I will explain how ultracold strontium atoms trapped by light can be used to create optical lattice clocks – the most precise timekeepers ever imagined. I am going to explain why these clocks are not only fascinating, but of crucial importance since they can help us to answer cutting- edge questions about complex many-body phenomena and magnetism, to unravel big mysteries of our universe and to build the next generation of quantum technologies.
Wednesday, 01 April 2026
Time Speaker Title Resources
09:00 to 09:40 Florian Schreck (University of Amsterdam, Amsterdam, Netherlands) Continuous Bose-Einstein condensation and optical clocks

Ultracold quantum gases are excellent platforms for quantum simulation and sensing. So far these gases have been produced using time-sequential cooling stages and after creation they unfortunately decay through unavoidable loss processes. This limits what can be done with them. For example it becomes impossible to extract a continuous-wave atom laser, which has promising applications for precision measurement through atom interferometry [1]. I will present how we achieve continuous Bose-Einstein condensation and create condensates (BECs) that persist in a steady-state for as long as we desire [2]. We are now using our new techniques also to tackle another challenge: the creation of continuously operating optical atomic clocks, which promise higher measurement bandwidth and better short term stability than traditional optical clocks that operate in a pulsed manner [3,4,5,6]. Finally I report on our work towards field-deployable optical lattice clocks [7,8].

References
[1] N. P. Robins, P. A. Altin, J. E. Debs, and J. D. Close, Atom lasers: Production, properties and prospects for precision inertial measurement, Physics Reports 529, 265 (2013).
[2] C.-C. Chen, R. González Escudero, J. Minář, B. Pasquiou, S. Bennetts, and F. Schreck, Continuous Bose-Einstein condensation, Nature 606, 683 (2022).
[3] M. A. Norcia, M. N. Winchester, J. R. K. Cline, and J. K. Thompson, Superradiance on the millihertz linewidth strontium clock transition, Sci. Adv. 2, e1601231 (2016).
[4] J. Chen, Active Optical Clock, Chinese Science Bulletin 54, 348 (2009).
[5] D. Meiser, J. Ye, D. R. Carlson, M. J. Holland, Prospects for a Millihertz-Linewidth Laser, PRL 102, 163601 (2009).
[6] M. Schioppo et al., Ultrastable optical clock with two cold-atom ensembles, Nature Photonics 11, 48 (2017).
[7] www.AQuRAClock.eu
[8] www.OpticsFoundry.com
09:40 to 10:20 Saptarishi Chaudhuri (Raman Research Institute, Bengaluru, India) A novel non-invasive detection protocol for cold atoms based on Raman Driven Spin Coherence measurements

I shall talk about non-invasive detection of spin coherence in a collection of Raman driven cold atoms using dispersive Faraday rotation fluctuation measurements, which opens possibilities of probing spin correlations in quantum gases and other similar systems. We can measure various atomic, magnetic and sub-atomic properties as well as perform precision magnetometry (sensing) using Spin Noise Spectroscopy (SNS) in an atomic ensemble and show that it has better resolution than typical absorption spectroscopy in detecting spectral lines.

I shall show a minimally perturbative detection method, based on Raman Driven SNS (RDSNS) to directly probe the local density of a cloud of cold atoms in real time. Unlike traditional fluorescence and absorption imaging techniques, this approach does not require stochastic photon scattering from trapped atoms, thereby leaving the cold cloud unperturbed. The data can be collected in MHz refresh rate, allowing for near real-time detection. This detection protocol is particularly advantageous for probing systems that lack inherent symmetry and can have important application in the domain of neutral atom based quantum computing platforms.

Reference:

1. Sayari Majumder, Bhagyashri Bidwai, Bernadette Varsha, Saptarishi Chaudhuri, Appl. Phys. Lett. 127, 044004 (2025)
2. S. Majumder and S. Chaudhuri, IEEE Transactions on Instrumentation and Measurement, vol. 74, pp. 1-10, 2025
10:50 to 11:30 Sanjukta Roy (Raman Research Institute, Bengaluru, India) Quantum Technology with ultra-cold Rydberg atoms

Atoms excited to Rydberg states with high principal quantum numbers exhibit exaggerated properties, such as large size, strong dipole-dipole interactions, large polarisabilities, and longer lifetimes compared to atoms in their ground state. These exotic characteristics and a high degree of controllability make ultra-cold Rydberg atoms versatile atomic building blocks for various quantum technologies such as scalable quantum information networks, precision Quantum Sensing, and secure Quantum Communications.
In this talk, I will give an overview of Quantum Technologies with Rydberg atoms and describe our results on Doppler-enhanced Quantum magnetometry using Rydberg atoms. I will also present our observations of the effects of interatomic interactions on the Autler-Townes splitting in cold Rydberg atoms. Finally, I will present our recent progress and future perspectives on Quantum Computing, Quantum sensing, and Quantum Simulation of Many-body physics with ultra-cold Rydberg atoms.
11:30 to 12:10 Abhishek Dhar (ICTS, Bengaluru, India) Hydrodynamic description of the dynamics of entanglement in a freely expanding fermionic gas

We consider a gas of non-interacting fermions that is released from a box into the vacuum and look at the entanglement between the escaped particles with those in the box. This provides a simple analytically tractable model that reproduces many features of the Page curve characterizing the evolution of entanglement entropy during evaporation of a black hole. Apart from the entropy we consider several other physical observables and show that the framework of generalized hydrodynamics provides a rather surprisingly accurate description of the quantum dynamics. We also report numerical results for interacting fermions.
12:10 to 12:50 Bindiya Arora (Guru Nanak Dev University, Amritsar, India) A Quantum Cyberinfrastructure for Rydberg Physics

Rydberg atoms have emerged as a leading platform for quantum simulation, sensing, and computation, with cold atom experiments increasingly reliant on reliable theoretical data for the design and interpretation of a wide range of measurements. While existing tools have served the community well, the next generation of quantum science demands a more accurate, flexible, and community-driven resource.

In this talk, I will present the key ideas for a new open-access Python-based cyberinfrastructure dedicated to Rydberg atom physics. Our approach goes beyond current non-relativistic models by solving the Dirac equation with a model potential, yielding high-quality wavefunctions and properties for both low-lying and high-lying Rydberg states. The package will deliver essential data including polarizabilities, finite-temperature lifetimes, and Rydberg-Rydberg interaction potentials, all critical for interpreting cold atom experiments.

Crucially, this infrastructure is built for and with the community. It is designed for ease of use, featuring a user-friendly graphical interface to make it accessible to experimentalists with limited programming background. The package will include a feedback mechanism for researchers to contribute new experimental data for refining theoretical models. This represents a small but significant step toward building indigenous capabilities within the Indian quantum community, while remaining firmly embedded in the broader global research ecosystem.

This talk will outline the key design concepts and numerical methods behind this initiative, and how we hope it will serve as a useful collaborative resource for the cold atom community.
14:30 to 15:10 Krishnendu Sengupta (IACS, Kolkata, India) Emergent prethermal Bethe integrability in a driven Rydberg chain

We study a chain of periodically driven Rydberg atoms and identify a class of drive protocols for which the driven chain exhibits emergent prethermal Bethe integrability at special drive frequencies. We provide a perturbative, analytic, expression of its Floquet Hamiltonian in the large drive amplitude regime. We demonstrate integrability of the leading term of this Floquet Hamiltonian at special drive frequencies, which we identify, by mapping it to the Hamiltonian of a XXZ spin chain. We support our analytical results by exact diagonalization studies on finite chain; our numerical results on level statistics, average magnetization, and spin-spin autocorrelation function of the driven chain brings out its integrable nature at these frequencies up to a large prethermal timescale. We discuss experiments that can test our theory.
15:10 to 15:50 Arti Garg (SINP, Kolkata, India) Exotic phases in periodically driven systems: Discrete time crystal in Sherrington-Kirkpatrick model and drive-induced unconventional superconductivity (Online)

Periodically driven quantum systems have been shown
to host novel non-equilibrium phases of matter that
are impossible to achieve in equilibrium systems. One
of the most remarkable examples of a non-equilibrium
phase of matter is a discrete-time crystal (DTC) that
spontaneously breaks discrete time-translation symmetry, resulting in persistent oscillations in physical observables. In the first part of my talk, I will discuss our recent work on periodically driven quantum Sherrington-Kirkpatrick (SK) model of Ising spin-glass in which all spins are randomly coupled. We investigated the possibilities of DTC phase in the SK model within three different driving protocols and found
that the quantum SK model exhibits a robust DTC phase despite the long-range nature of interactions. In the second part of my talk, I will talk about periodically driven weakly interacting Hubbard model and its variants and show how periodic drive can transform this weakly interacting system into a strongly interacting system, frustrates the AFM order and stabilizes unconventional superconductivity even at half-filling.
15:50 to 16:10 Sejal Ahuja (HRI Allahabad, India) Expediting quantum state transfer through the long-range extended XY model

Going beyond short-range interactions, we explore the role of long-range interactions in the extended XY model for transferring quantum states through evolution. In particular, employing a spin-1/2 chain with interactions decaying as a power law, we demonstrate that long-range (LR) interactions significantly enhance the efficiency of a quantum state transfer (QST) protocol, improving the achievable fidelity, mitigating its slow decline as compared with the nearest-neighbor setting, associated with increasing system-size. Our study identifies the LR regime as providing an optimal balance between interaction range and transfer efficiency, outperforming the protocol with the short-range interacting model. Our detailed analysis reveals the impact of system parameters, such as anisotropy, magnetic field strength, and coordination number, on QST dynamics. Specifically, we find that intermediate coordination numbers lead to a faster and more reliable state transfer, while extreme values diminish performance. Furthermore, we exhibit that the presence of LR interactions considerably reduces the minimum time required to achieve fidelity beyond the classical limit. In addition, we analyze the impact of non-Hermiticity in the quantum state transmission by employing a non-Hermitian spin chain that functions as a quantum data bus.
16:30 to 17:30 Ana Maria Rey (University of Colorado, Boulder, USA) New frontiers in quantum simulation and sensing via cavity mediated interactions (CL-2)

Atoms and photons are the fundamental building blocks of our universe. Their interactions rule the behavior of our physical world but at the same time can be extremely complex, especially in the context of many-body quantum systems. Understanding and harnessing them is one of the major challenges of modern quantum science. In recent years, ultracold atomic systems have emerged as a pristine platform for the exploration of atom-light interactions. In this lecture, I will discuss the potential of atomic systems loaded in optical cavities as a resource to enhance the energy scales needed to observe complex many-body behaviors by harnessing infinity range interactions mediated by photons that can couple a large set of internal levels. I will show how cavity systems can help us not only to shed light on behaviors of iconic Hamiltonians describing real materials but also to engineer broader classes of Hamiltonians with multi-body interactions too complex to emerge naturally. Furthermore , I will explain how they can facilitate the generation of quantum entanglement and overcome physical constraints currently limiting the performance of state-of-the-art atomic clocks and interferometers.
Thursday, 02 April 2026
Time Speaker Title Resources
09:00 to 09:40 Sadhan Kumar Adhikari (Sao Paulo State University, Brazil) Novelties in a strongly dipolar Dy condensate

A strongly dipolar condensate, composed of atoms with large magnetic dipole moments, exhibits many remarkable phenomena. I will discuss some of these characteristics of a strongly dipolar condensate. It has been established in different theoretical and experimental studies that, when the number of atoms is increased, a strongly dipolar Dy Bose-Einstein condensate, confined by a quasi-two-dimensional (quasi-2D) trap, becomes unstable against the formation of multiple droplets and undergoes a spontaneous phase transition to a solid-like crystalline phase, where the droplets are arranged in a spatially periodic lattice in the $x$-$y$ plane. The quasi-2D trap has a stronger confinement along the polarization $z$ direction of dipolar atoms and a weaker confinement in the $x$-$y$ plane. We show that if the traps in the $x$-$y$ plane are removed, the strongly dipolar condensate remains in the crystalline phase to form a self-bound quasi-2D crystal of droplets. If the traps in the $x$-$y$ plane are made stronger to approach the three dimensional limit, the condensate takes the form of a hollow cylinder, which, when rotated about the $z$ axis, can host stable giant vortices of angular momentum greater than unity.
09:40 to 10:20 Valentin Walther (Purdue University, West Lafayette, USA) Few-body Rydberg interactions and blockade (Online)

Polarization forces are ubiquitous in nature, spanning both animate and inanimate systems. They are most commonly described in terms of pairwise interactions. In this talk, we explore two settings in which this binary description breaks down, revealing the importance of genuine few-body effects.

In the first part, we revisit the validity of the pairwise approximation in lattice systems of Rydberg atoms. We identify regimes where the binary picture holds, as well as conditions under which additional interaction terms become essential. In particular, we highlight special regimes near a Förster resonance where three-body interactions are strongly enhanced. We discuss ongoing efforts to derive effective low-energy Hamiltonians and to characterize the resulting many-body quantum behavior in and around these regimes.

In the second part, we turn to Rydberg macrodimers, diatomic molecules with micron-scale bond lengths. These systems exhibit remarkable single-molecule properties, including a spectrum of shallow vibrational states that have recently been probed using quantum gas microscopy. We compute the intermolecular interactions between macrodimers, which arise from the Rydberg character of their constituent atoms, and map out the resulting anisotropic molecular potentials. Based on this, we predict a molecular excitation blockade and present comparisons with experimental data that provide first evidence of this effect.
10:50 to 11:30 Umakant Rapol (IISER Pune, India) Quantum Diffusion and Localization Dynamics in Atom-Optics Kicked Rotors

The quantum kicked rotor (QKR) is a foundational model for examining transport phenomena and dynamical localization within the framework of quantum chaos. By applying periodic, deterministic pulses to a system, the QKR enables the observation of transitions from diffusive to localized states—a result of quantum interference. This momentum-space dynamical localization serves as a mathematical analogue to Anderson localization in disordered solids, where interference effects suppress transport. Our research group realizes this model using atom-optics kicked rotors, where laser-cooled atoms in optical lattices are subjected to periodic kicks from pulsed laser fields.

In our first investigation, we analyzed the influence of nonstationary Lévy noise within the kick sequence. We found that this noise induces a slower-than-exponential decoherence, resulting in quantum subdiffusion. This phenomenon is highly dependent on the Lévy exponent, providing a tunable method for regulating quantum transport. Subsequently, we modified the kick dynamics by periodically reversing the sign of the kick sequence through half-Talbot time free evolution. This modification led to a period of enhanced diffusion followed by asymptotic localization, yielding localized wave function profiles with non-exponential characteristics that indicate a complex relationship between diffusive and localizing forces. Finally, we utilized the kicked rotor setup to investigate asymmetric dynamical localization. By incorporating half-Talbot time evolution between kicks, we produced an asymmetric momentum distribution sensitive to the initial velocity of the Bose-Einstein condensate (BEC). This effect allowed for high-sensitivity detection of BEC micromotion, enabling the precise measurement of minute initial velocities.
11:30 to 12:10 Pankaj Kumar Mishra (IIT Guwahati, India) Structure and turbulent dynamics of quantum droplet

Quantum droplets (QDs) have recently emerged as a novel state of matter in ultracold atomic systems, where self-bound states arise from the interplay between mean-field (MF) interactions and beyond-mean-field (BMF) quantum fluctuations. While in higher dimensions droplets typically form due to attractive MF and repulsive BMF contributions, in one-dimensional binary systems the mechanism is reversed, with repulsive MF balanced by attractive BMF interactions. In the first half of this talk, we focus on the structure and dynamics of quantum droplets in one-dimensional spin–orbit coupled binary Bose–Einstein condensates, presenting numerical results on how both vanishingly small and finite MF interactions affect droplet stability, shape, and evolution. We also discuss dynamical responses induced by velocity perturbations, quenches in spin–orbit or Rabi coupling, and control of droplet properties via population imbalance between pseudo-spin components. In the second part of the talk, we turn to turbulent dynamics in two-dimensional condensates, where turbulence is generated using a rotating external paddling potential. By tuning the rotation strength and angular velocity, we identify different turbulent regimes, including vortex dipoles, vortex clusters, and randomly distributed vortex–antivortex pairs, and analyze their corresponding energy spectra, revealing Kolmogorov- and Vinen-type scaling behaviors in different configurations.
12:10 to 12:50 Subhro Bhattacharjee (ICTS, Bengaluru, India) TBA
14:30 to 15:10 Luis Santos (Leibniz University, Hannover, Germany) Ultra-cold dipoles in triangular optical ladders (Online)

Experiments on dipolar quantum systems (magnetic atoms, polar molecules, Rydberg atoms) are opening interesting possibilities for the quantum simulation of spin models of interest in quantum magnetism. In particular, dipoles in triangular ladders (made with optical lattices or tweezer arrays) may allow for the interplay between frustration and long-range interactions, allowing for the realization of intriguing phases and phase-transitions, such as a dipole-induced transition between a chiral-superfluid and a non-chiral two-component superfluid, or the realization of chiral and nematic spin phases [1]. Interestingly, dipolar bosons in triangular ladders may realize an intriguing state, the so-called anyon condensate [2]. I will comment on what is meant here with anyons, and discuss first results that show that properly-tuned dipoles can be employed to realize this peculiar state [3].

 

[1] A. Dasgupta, M.Lacki, H. Korbmacher, G. A. Dominguez-Castro, J. Zakrzewski, and Luis Santos, PRA 113, L031301 (2026)

[2] C. D. Batista, and R. D. Somma, Phys. Rev. Lett. 109, 227203 (2012).

[3] A. Dasgupta and L. Santos, on-going.
15:10 to 15:50 Weibin Li (University of Nottingham, Nottingham, UK) TBA (Online)
15:50 to 16:10 Kritika Jain (IISER Pune, India) Efficient Long-Range Entanglement and Controllable Chiral Emission in Composite Nanofiber Waveguides

Efficient light-matter interfaces are a cornerstone for scalable quantum technologies, with nanophotonic platforms offering unprecedented control over light-matter interactions. In this work, we propose and analyze a composite waveguide system consisting of two parallel optical nanofibers to significantly enhance photon-emitter interactions. Using a full 3D Green’s tensor formalism, we develop a rigorous and computationally efficient framework to capture the full radiation dynamics, including both guided and radiation modes.

We show that the composite geometry leads to a substantial enhancement in photon coupling efficiency compared to single nanofiber systems, resulting in stronger and more robust long-range entanglement between emitters [1]. Furthermore, the system enables tunable, position-dependent chiral emission, providing precise control over photon directionality for efficient quantum state routing. We also observe superradiant and subradiant collective states in arrays of emitters, where long-lived subradiant modes can be exploited for quantum memory applications. These results establish composite nanofiber platforms as a promising route toward scalable fiber-based quantum technologies.

References:

[1] K. Jain, L. Ruks, F. Le Kien, and T. Busch, “Strong dipole-dipole interactions via enhanced light-matter coupling in composite nanofiber waveguides,” Phys. Rev. Research 6, 033311 (2024).
16:30 to 17:30 Ana Maria Rey (University of Colorado, Boulder, USA) S, P, D… BEC… Easy as I, II, III: Pairing Games in a Cavity (CL-3)

Superconductors are defined not just by whether electrons pair, but by how they pair. When multiple pairing symmetries compete, entirely new quantum phases can emerge — including topological states with protected edge currents. Yet in real materials, this competition is notoriously difficult to isolate and control.
In this lecture, I will introduce a cavity QED quantum simulator based on ultracold atoms in an optical lattice, where cavity photons mediate long-range interactions whose strength and symmetry can be tuned. Using an Anderson pseudospin mapping, I will explain how to realize superconducting phases with tunable symmetry, from conventional s-wave to topological p -wave and d-wave orders. I will also discuss our recent observation of  the three dynamical phases of an s-wave BCS superconductor and how we directly tracked the order parameter in real time via non-destructive cavity measurements. More broadly, I will explain how this platform establishes a new paradigm for engineering and probing superconductivity in synthetic quantum matter.
Friday, 03 April 2026
Time Speaker Title Resources
09:00 to 09:40 Bodhaditya Santra (IIT Delhi, India) Quantum computing and sensing using neutral atoms and high precision lasers

The rich internal structure of atoms provides unique platform to study various quantum phenomena by high precision quantum initial state engineering, manipulation and final state detection. The unprecedented controllability of various quantum states in atomic systems can be achieved by using high precision lasers and magnetic fields. In this talk I will present the recent progress in our lab towards building a neutral atom quantum computer and quantum sensors. I will also discuss the importance and market opportunity of indigenous subcomponents such as lasers, electronics and ultrahigh-vacuum chambers required for building utility scale quantum instruments.
09:40 to 10:20 Paulsamy Muruganandam (Bharathidasan University, Tiruchirappalli, India) TBA
10:20 to 10:40 Koushik Mukherjee (The University of Electro-Communications, Tokyo, Japan) Collective Excitations and Higgs-like Amplitude Modes in Dipolar Supersolids

Supersolids, quantum phases that simultaneously exhibit crystalline order and superfluidity, provide a unique platform to explore the interplay of broken continuous symmetries and collective excitations. In this presentation, we will discuss the excitation spectrum of dipolar quantum gases across the superfluid-to-supersolid phase transition, with particular emphasis on the emergence and detection of amplitude (Higgs) modes.
Higgs-like amplitude modes are notoriously difficult to observe in condensed matter systems, including supersolids in harmonic potentials. To mitigate this mode coupling, we consider toroidal trapping potentials, whose continuous rotational symmetry and periodic boundary conditions along the azimuthal direction establish a direct connection between experimentally accessible finite-size systems and bulk supersolids described within mean-field theory. Within this framework, we compute the elementary excitation spectrum across the phase transition and demonstrate the emergence of first sound, second sound, and Higgs amplitude modes in dipolar supersolids.
Furthermore, we propose an interferometric protocol to probe Higgs amplitude excitations by exploiting the temporal Talbot effect in a toroidal geometry. This approach enables the creation and real-space detection of localized Higgs wave packets. The resulting “quantum carpet” dynamics reveal the quadratic dispersion of amplitude modes and allow for a direct extraction of the effective mass of the Higgs quasiparticle from revival times.
10:40 to 11:00 Nalinikanta Pradhan (IIT Guwahati, India) Proposals for realizing a Josephson diode in Atomtronic circuits

The Josephson diode effect (JDE) has gained significant interest recently due to its potential applications in cryogenic circuits, quantum computing, and realizing novel superconducting devices. Despite having remarkable applications, this non-reciprocal transport phenomenon has not been explored in atomtronic circuits, which promise to offer exceptional control over system geometry, disorders, and atomic interactions. We propose and numerically demonstrate, to our knowledge, the first atomtronic implementation of a Josephson diode, based on a ring-shaped Bose–Einstein condensate with optical barriers serving as Josephson junctions. We realize the required inversion symmetry breaking through asymmetric barrier placement and an asymmetric alternating current (AC) drive, enabling position- and drive-tunable diode effects with efficiencies up to 15% and 91%, respectively. While the standard time-of-flight absorption imaging technique can readily observe these effects, we employ cavity optomechanics for cleaner, in situ, real-time, and non-destructive measurements of the Josephson dynamics. Our results establish a highly tunable platform for nonreciprocal Josephson transport, opening avenues for diode-based neutral-atom technologies in future quantum circuits.
11:20 to 11:40 Nilanjan Roy (NISER, Bhubaneswar, India) Emergent critical phases in disordered quantum systems

Critical points in disordered quantums system are very special points in the parameter space where localization transitions happen. Moreover, near-critical points have been proposed for enhanced quantum sensing. However, these critical points are very fine-tuned and fragile under external perturbations. For example, the paradigmatic Aubry-Andre-Harper (AAH) model in one dimension where all the single-particle eigenstates undergo the delocalization-localization transition at the critical strength of the quasiperiodic potential, protected by self-duality. Hence, two relevant questions are in order: can the self-duality (criticality) re-emerge in the AAH model even with duality-breaking perturbation? Can we obtain a broadened critical phase, instead of a point, in a quasiperiodic chain in presence of interactions? I will briefly talk about our recent works addressing these two questions.
11:40 to 12:00 Pragna Das (Jozef Stefan Institute, Ljubljana, Slovenia) A detailed study on various phases in dissipative anisotropic Dicke model

I will present a comprehensive study of different phases in the Dicke model incorporating both anisotropy and dissipation. I will begin with a concise review of the quantum phase transition in this setting, highlighting how these two parameters shift the critical point. I will then present a detailed investigation of the transition from ergodic to nonergodic phases by analyzing the eigenvalue and eigenvector properties of the Liouvillian, utilizing the scaling of the Liouvillian gap and the average participation ratio. Our results demonstrate that the eigenvector properties of the Liouvillian are consistent with its spectral characteristics, resulting in a phase diagram that shares similarities with its closed-system counterpart. Furthermore, I will show that the Liouvillian gap exhibits distinct scaling behaviors in these two phases. Finally, I will extend the study to the driven case by applying a Thue–Morse quasiperiodic drive. In this case, we find that bosonic dissipation plays a crucial role in stabilizing the prethermal plateau, offering an effective mechanism to halt the heating induced by the quasiperiodic drive.
12:00 to 12:20 Saptarshi Saha (Technische Universität Berlin, Berlin, Germany) Beyond equal-time correlations in quantum optical systems : a cumulant based approach

Recent advances in the cumulant expansion scheme have been proven beneficial for studying the dynamics of many-body open quantum systems. In this presentation, I will introduce a generalized framework for calculating unequal-time correlation functions within the cumulant expansion approach. As a part of the formalism, I will propose an ansatz that enables the implementation of the quantum regression theorem. To validate this method, I will apply it to cascaded optical systems and compute many-body correlations, comparing the results against exact simulations. I will also discuss the domains of validity of our approach and the factors that constrain its performance. Overall, this approach offers a powerful tool for investigating correlated dynamics in complex quantum systems.