Quantum Information Theory Group
Indian Institute of Technology Palakkad
Research
Entanglement Theory
In the last two decades, correlation measures originating from the entanglement-separability paradigm have attracted a lot of attention, and substantial theoretical as well as experimental advancements in detecting and computing such measures have been achieved in a bipartite scenario. However, quantifying entanglement in multipartite domain still remains a challenging task. Our research aims to address the problem of characterizing, detecting, and quantifying quantum entanglement in multiparty domain, and developing strategies for reducing the computational resource required in calculation of there quantum correlation measures.
Quantum Many-Body Systems
Quantum many-body systems are considered as ideal candidate systems to carry out quantum information processing tasks. They are crucial for the realizations of quantum protocols like quantum state transfer via a spin-chain, and measurement-based quantum computation. This highlights the necessity for a better understanding of the novel phases and phenomena occurring in quantum many-body systems using a language consistent with quantum information theory. This is achieved by investigating the quantum correlations, such as entanglement, that are of importance for quantum information processing tasks to be performed in these quantum many-body systems. Our research deals with the static as well as dynamical trends of entanglement measures in quantum many-body systems leading to its efficient characterization. Implementation of quantum protocols in the laboratory setting forces one to deal with noisy open quantum systems, which results in decoherence, thereby posing an obstacle in front of realizing quantum technologies. It is, therefore, crucial to investigate how quantum correlations behave under different types of noise, when the system is in contact with one or many environments. These environments can be thermal as well as non-thermal in nature. Our research in open quantum system focusses on quantum many-body systems considered as candidate systems for different quantum information processing tasks, and aims to develop strategies for protecting quantum correlations against noisy in these systems.
Apart from the quantum many-body systems useful in quantum information processing, we are also interested in the physics of exactly solvable quantum many-body models.
Open Quantum Systems
Implementation of quantum protocols in the laboratory setting forces one to deal with noisy open quantum systems, which results in decoherence, thereby posing an obstacle in front of realising quantum technologies. It is, therefore, crucial to investigate how quantum correlations behave under different types of noise, when the system is in contact with one or many environments. These environments can be thermal as well as non-thermal in nature. Our research in open quantum system focusses on quantum many-body systems considered as candidate systems for different quantum information processing tasks, and aims to develop strategies for protecting quantum correlations against noisy in these systems.
Topological Quantum Codes
Immense effort is being given all over the world towards implementing large-scale fault-tolerant quantum computers, having potential to solve problems that are intractable by existing classical computers, such as simulating large quantum systems, efficient decryption of codes, etc. Towards this aim, topological quantum error correcting (QEC) codes, such as the surface codes and the colour codes, have emerged as the most promising candidates. These topological quantum codes are interacting quantum spin systems constituted of spin-1/2 particles, which represents the physical qubits, arranged on lattices of specific geometry, and the ground states of these systems are used as resource states in quantum error correction.
Generally the figures of merit of these quantum states to be used in a quantum protocol are quantum correlations, such as entanglement, which can be used as resource in that quantum protocol. However, it is known that in order to perform successful error correction using these states in a laboratory setup, taking into account errors on multiple physical qubits, one needs to deal with large systems in the presence of noise. This makes the characterisation of these systems using entanglement measures difficult. Our research aims to quantify and compute bipartite as well as multiparty entanglement in subsystems of a large-scale quantum many-body system like the topological quantum codes in the presence of noise.
Quantum Thermodynamics
Quantum thermodynamics aims to design effective quantum thermal machines in order to understand thermodynamic principles at the quantum mechanical level, and to explore whether these machines can provide quantum advantages over their classical counterparts. It has grown to become a thriving multidisciplinary field of research, including statistical physics, quantum information theory, the theory of open quantum systems, and quantum many-body physics. Among the quantum thermal machines, small quantum absorption refrigerators, constituted off a small number of qubits and/or qutrits are the focus of our research. We study the different models and properties of these machines from a quantum information perspective, using the formalism of open quantum systems. We also investigate possible construction of such machines using low-dimensional quantum spin models.