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 such as optical waveguide lattices. Under the framework of quantum channels, I have investigated the notion of process resource-breaking maps, which can render quantum states useless for information-theoretic and computational tasks without destroying their inherent resource. I have worked in the field of quantum metrology by studying 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.

Dimensional advantage in secure information trading via the noisy dense coding protocolThe quantum dense coding (DC) protocol, which has no security feature, deals with the transmission of classical information encoded in a quantum state by using shared entanglement between a single sender and a single receiver. Its appropriate variant has been established as a quantum key distribution (QKD) scheme for shared two-qubit maximally entangled states, with the security proof utilizing the uncertainty relation of complementary observables and the Shor-Preskill entanglement purification scheme. We present the DC-based QKD protocol for higher dimensional systems and report the lower bounds on secret key rate, when the shared state is a two-qudit maximally entangled state, and mixtures of maximally entangled states with different ranks. The analysis also includes the impact of noisy channels on the secure key rates, before and after encoding. In both the noiseless and the noisy scenarios, we demonstrate that the key rate as well as the robustness of the protocol against noise increases with the dimension. Further, we prove that the set of useless states in the DC-based QKD protocol is convex and compact.

Multimode advantage in continuous variable quantum batteryWe provide an architecture for a multimode quantum battery (QB) based on the framework of continuous variable (CV) systems. We examine the performance of the battery by using a generic class of multimode initial states whose parameters can be tuned to produce separable as well as entangled states and that can be charged locally as well as globally by Gaussian unitary operations. Analytical calculations show that a separable state is equally advantageous as an entangled one for two- and three-mode batteries when taking the figures of merit as the second moments of the change in energy. In order to produce a stable quantum battery consisting of an arbitrary number of modes, we derive compact analytical forms of the energy fluctuations and prove that for a multimode separable Gaussian initial state, fluctuations decrease as the number of modes increases, thereby obtaining a scaling analysis. Moreover, we demonstrate that local displacement as a charger is better to minimize the fluctuations in energy than that involving the squeezing unitary operation.

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 and

Senior lecturer

Queen's University Belfast

Himadri Sekhar Dhar

Assistant Professor

Indian Institute of Technology, Bombay

Tamoghna Das

Assistant Professor

Indian Institute of Technology, Kharagpur

Shiladitya Mal

Associate Professor

Chennai Institute of Technology

Shashank Gupta

Postdoctoral Researcher

Okinawa Institute of Science and Technology

Saptarshi Roy

Postdoctoral Researcher University of Hong Kong

Srijon Ghosh

Postdoctoral Researcher

University of Warshaw

Ayan Patra

Senior Research Fellow

Harish Chandra Research Institute

Tanoy Kanti Konar

Senior Research Fellow

Harish Chandra Research Institute

Sudipta Das

Junior Research Fellow

Indian Institute of Technology, Bombay

Abhishek Muhuri

Research Fellow

International Institute of Information Technology, Hyderabad

Talks and Posters

1. 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)

2. 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)

3. Communication protocols in the quantum paradigm

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

4. 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)

5 .Noise-augmented Dense-coding network and its optical implementation

Young Quantum, 2023

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

6. Quantum Illumination with imperfections

Quantum Information Processing, 2023

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

7. 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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