Research on Quantum Information theory and

Continuous Variable systems

My current research involves identifying resources for efficient quantum computing through bosonic architectures in optical, superconducting, and microwave platforms. The project aims to analyze the resource theoretics of genuine quantum advantage, including constructing operational measures and verifying quantum supremacy. I aim to develop a multi-resource theory that explains the computational speedup predicted in the quantum domain. I have started analyzing the concept of quantum magic and aim to develop operational measures, especially in continuous variable systems. I have explored quantum communication protocols, both in bipartite and multiparty settings, and have tried to identify the resources responsible for providing non-classical performance. I have also investigated quantum key-distribution protocols using high-dimensional discrete variable systems. I am interested in the theory of the generation, detection, and quantification of quantum correlations in physically realizable platforms. Under the framework of quantum channels, I have investigated the notion of process resource-breaking maps and magic-breaking ones, which can render quantum states useless for information-theoretic and computational tasks without destroying their inherent resource. I have analyzed quantum illumination using non-Gaussian states and in the presence of lossy targets. My doctoral thesis comprised the study of quantum correlation measures - bipartite, multipartite, and measurement-based - through the lens of random quantum states, a concept I wish to study using continuous variables. My future goals include studying the dynamical resource theory of preservability, secure communication protocols using continuous variable modes of light, and exploring the role of fractional calculus in quantum information theory. I am especially interested in learning about quantum error correction and its realization in continuous variable systems, the fascinating concept of indefinite causal order, and how it can boost existing information-theoretic protocols. Click here to see my list of publications.

My research lifelines

Featured Research

Information theoretic resource-breaking channelsWe present a framework of channels that break the resource associated with a given quantum information processing task, in which entanglement is not adequate. In particular, we illustrate our proposed notion, referred to as process resource-breaking channels, by examining two important communication protocols, quantum dense coding, and teleportation. We prove that the sets of dense coding (DBT) and teleportation resource-breaking channels (TBT) are convex and compact, and identify a specific class of classical-quantum channels as the extreme points of those sets. We provide sufficient conditions for a channel to be in TBT or DBT, when they are group-covariant along with having the ability to transform a maximally entangled state into a useless one. We also establish sufficient requirements on unital qubit channels to break the dense codeability of any resource shared by one or more senders and a single receiver. Regarding teleportation, we prove that the set TBT in the qubit regime is equivalent to that of qubit entanglement-breaking channels provided pre-processing is allowed. Furthermore, we construct witness operators capable of identifying non-TBT(non-DBT) maps.

Sequential information theoretic protocols in continuous variable systemsIn order to enable the sequential implementation of quantum information theoretic protocols in the continuous variable framework, we propose two schemes for resource reusability, resource-splitting protocol and unsharp homodyne measurements. We demonstrate the advantage offered by the first scheme in implementing sequential attempts at continuous variable teleportation when the protocol fails in the previous round. In the second scheme, unsharp quadrature measurements are employed to implement the detection of entanglement between several pairs of observers. Under specific conditions, our calculations show that it is possible to successfully witness the entanglement of the same two-mode state, sequentially by as many as five observers.

Limits on broadcasting non-stabilizerness through unrestricted operationsIn the resource theory of non-stabilizerness, we prove that stabilizer operations cannot replicate or broadcast the "magic" resource of all quantum states in an arbitrary finite dimension. Moreover, we show that even in unrestricted scenarios, there are fundamental limits on cloning the non-stabilizerness content of quantum states. When using an auxiliary system as part of the cloning process, we show that it is impossible to broadcast the non-stabilizerness of qubits that possess a greater degree of non-stabilizerness than the known states on which the transformations are based. We also derive the conditions to broadcast magic perfectly using unrestricted operations. Furthermore, we compare non-stabilizerness broadcasting with traditional state cloning methods, such as state-dependent and -independent cloners, which can achieve perfect broadcasting of states with known magic content. Our findings reveal that state-dependent cloning unitaries designed for specific states have lower average non-stabilizerness-generating power than magic-generating unitaries.

Quantum dense coding network using multimode squeezed states of lightWe present a framework of a multimode dense coding network with multiple senders and a single receiver using continuous variable systems. The protocol is scalable to arbitrary numbers of modes with the encoding being displacements while the decoding involves homodyne measurements of the modes after they are combined in a pairwise manner by a sequence of beam splitters, thereby exhibiting its potentiality to implement in laboratories with currently available resources. We compute the closed form expression of the dense coding capacity for the cases of two and three senders that involve sharing of three- and four-mode states, respectively. The dense coding capacity is computed with the constraint of fixed average energy transmission when the modes of the sender are transferred to the receiver after the encoding operation. In both the cases, we demonstrate the quantum advantage of the protocol using paradigmatic classes of three- and four-mode states. The quantum advantage increases with the increase in the amount of energy that is allowed to be transmitted from the senders to the receiver.

Collaborators

Aditi Sen (De)

Professor H

Harish Chandra Research Institute

Alessandro Ferraro

Associate Professor

University of Milan

Giulia Ferrini

Professor

Chalmers University of Technology

Ulysse Chabaud

INRIA permanent researcher

École Normale Supérieure de Paris

Himadri Sekhar Dhar

Assistant Professor

Indian Institute of Technology, Bombay

Tamoghna Das

Assistant Professor

Indian Institute of Technology, Kharagpur

Rui Wang

Doctoral Student

Chalmers University of Technology

Ayan Patra

Senior Research Fellow

Harish Chandra Research Institute

Tanoy Kanti Konar

Postdoctoral Researcher

Jagiellonian University, Krakow

Srijon Ghosh

Postdoctoral Researcher

University of Palermo

Sudipta Mondal

Senior Research Fellow

Harish Chandra Research Institute

Akhil Kumar Awasthi

Junior Research Fellow

Harish Chandra Research Institute

Mrinmoy Samanta

Junior Research Fellow

Harish Chandra Research Institute

Debkanta Ghosh

Senior Research Fellow

Harish Chandra Research Institute

Sudipta Das

Junior Research Fellow

Indian Institute of Technology, Bombay

Saptarshi Roy

Postdoctoral Researcher

Seoul National University

Abhishek Muhuri

Research Fellow

International Institute of Information Technology, Hyderabad

Shiladitya Mal

Associate Professor

Chennai Institute of Technology

Shashank Gupta

Assistant Professor

Indian Institute of Technology, Indore

Talks and Posters

Non-Gaussianity - an operational resource for quantum computation

at Department of Physics, University of Calcutta (08/04/2026)

Non-Gaussian rank - an operational measure of quantum non-Gaussianity

at Harish Chandra Research Institute, Prayagraj, India (01/04/2026)

Non-Gaussian rank: an operational measure of quantum non-Gaussianity

Veriqub Consortium Meeting

at International Iberian Nanotechnology Laboratory, Braga, Portugal (19/01/2026 - 23/01/2026)

Non-Gaussian rank - an operational monotone of non-Gaussianity

5th Applied Quantum Mechanics Meeting

at Università degli Studi di Milano, Milan, Italy (02/12/2025)

Non-Gaussianity as a resource in quantum information and computational protocols

at Chalmers University of Technology, Gothenberg, Sweden (08/10/2025)

Non-Gaussian rank as an operational measure of non-Gaussianity

XVII Italian Quantum Information Science Conference

Bologna, Italy (08/09/2025 - 12/09/2025)

Process resource breaking channels: the case for magic in universal quantum computation

at Quantum Resources 2025, Jeju, South Korea (17/03/2025 - 21/03/2025)

Distributed dense coding network for continuous variable systems

at Center for Quantum Science and Technology, Center for Security Theory Algorithmic Research, The International Institute of Information Technology, Hyderabad (03/01/2023)

Communication protocols in the quantum paradigm

at Condensed Matter Physics Research Centre, Jadavpur University, (12/10/2023)

Generation and destruction of information-theoretic resources

Meeting on Quantum Information Processing and Applications, 2023

at Harish Chandra Research Institute (04/12/2023 - 10/12/2023)

Noise-augmented Dense-coding network and its optical implementation

Young Quantum, 2023

at Harish Chandra Research Institute (15/02/2023 - 18/02/2023)

Quantum Illumination with imperfections

Quantum Information Processing, 2023

at California, USA (07/03/2023 - 11/03/2023) [online]

Constructive Feedback of Non-Markovianity on Resources in Random Quantum States

Young Quantum, 2022

at Harish Chandra Research Institute (12/10/2022 - 15/10/2022) [online]

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