Quantum Information and Computation Group at HRI

Congratulations to Sudipta Mondal for his first work in Quantum Information theory.

Duality between imperfect resources and measurements for propagating entanglement in networks We propose a measurement-based entanglement propagation strategy for networks in which all nodes except two are initially occupied by a suitably chosen single-qubit system and the two nodes share a bipartite noisy entangled state. The connections between the sites are established using unsharp two-q...

Congratulations to Debkanta Ghosh for his first work in Quantum Information theory.

Entanglement of weighted graphs uncovers transitions in variable-range interacting models The cluster state acquired by evolving the nearest-neighbor (NN) Ising model from a completely separable state is the resource for measurement-based quantum computation. Instead of an NN system, a variable-range power law interacting Ising model can generate a genuine multipartite entangled (GME) we...

Congratulations to Debarupa on her first work in Quantum Information theory.

Entanglement is indispensable for masking arbitrary set of quantum states We question the role of entanglement in masking quantum information contained in a set of mixed quantum states. We first show that a masker that can mask any two single-qubit pure states, can mask the entire set of mixed states comprising of the classical mixtures of those two pure qubit states as w...

Congratulations to Ayan Sahoo on his first work in Quantum Information theory.

Localization Driven Quantum Sensing We show that the delocalization-localization transition in a quantum-many body (QMB) systems is a compelling quantum resource for achieving quantum-enhanced sensitivity in parameter estimation. We exploit the vulnerability of a near-transition QMB state against the parameter shift for devising effic...

Congratulation to Paranjoy on his first work in Quantum Information and Computation Group at HRI

Effects of detection loophole on rival entanglement attestation techniques Loopholes present in an experimental set-up can significantly affect the reliability of entanglement detection. We discuss two methods for detection of entanglement: one is by using the positive partial transposition criterion after quantum state tomography and the other by estimating the second and...

Congratulations to Swati on her first work in Quantum Information.

All multipartite entanglements are quantum coherences in locally distinguishable bases We find that the m-separability and k-partite entanglement of a multipartite quantum system is correlated with quantum coherence of the same with respect to complete orthonormal bases, distinguishable under local operations and classical communication in certain partitions. In particular, we show th...

Congratulations to Abhishek Muhuri on his first work in quantum information.

Superiority in dense coding through non-Markovian stochasticity We investigate the distributed dense coding (DC) protocol, involving multiple senders and a single or two receivers under the influence of non-Markovian noise, acting on the encoded qubits transmitted from senders to the receiver(s). We compare the effects of non-Markovianity on DC both for the deph...

Congratulations to Sayan Mondal for his first work in Quantum Information.

Estimating phase transition of perturbed J1-J2 Heisenberg quantum chain in mixtures of ground and first excited states We show that the nearest neighbour entanglement in a mixture of ground and first excited states - the subjacent state - of the J1-J2 Heisenberg quantum spin chain can be used as an order parameter to detect the phase transition of the chain from a gapless spin fluid to a gapped dimer phase. We study...

Congratulations to Prof. Aditi Sen De on becoming a fellow of the Indian National Science Academy.

The following link is a postdoc ad to work at HRI within QuEST, DST. Please share and disperse the information to potentially interested people.

http://www.hri.res.in/~omnotices/admin/project/Advt-QuEST-DST-2022-Prof-Ujjwal-Sen.pdf

Congratulations to Keshav Das Agarwal for his first paper from the QIC group at HRI, Congrats to Ganesh as well for his hard work.

Predicting Critical Phases from Entanglement Dynamics in XXZ Alternating Chain The quantum XXZ spin model with alternating bond strengths under magnetic field has a rich equilibrium phase diagram which includes Haldane, Luttinger liquid, singlet, and paramagnetic phases. We show that the nearest neighbor bipartite and multipartite entanglement can detect quantum critical lines...

Congratulations Pritam Halder for his first paper from the QIC group at HRI. I am sure, in coming years, we will be able to see many more interesting results reported by you. Congrats Shiladitya Mal for another work!

Measurement-based Multipartite Entanglement Inflation Generating entanglement between more parties is one of the central tasks and challenges in the backdrop of building quantum technologies. Here we propose a measurement-based protocol for producing multipartite entangled states which can be later fed into some network for realizing suitable quantum p...