dc.contributor.advisor | Garani, Shayan Srinivasa | |
dc.contributor.author | Raina, Ankur | |
dc.date.accessioned | 2021-04-12T09:29:54Z | |
dc.date.available | 2021-04-12T09:29:54Z | |
dc.date.submitted | 2019 | |
dc.identifier.uri | https://etd.iisc.ac.in/handle/2005/5053 | |
dc.description.abstract | Quantum entanglement is a unique phenomenon that occurs in quantum systems and ensures the
feasibility of tasks considered impossible in the classical world. Two such important tasks are
superdense coding and quantum teleportation. The strength of these protocols rests on the
availability of entangled quantum states, such as the bipartite Bell states. When entanglement is
shared among many systems, it gives rise to a richer class of multipartite entangled states. One of
the popular multipartite quantum states that are successfully prepared by experimentalists are the
graph states. Construction of graph states is as follows: Every node has a qubit and the nodes are
connected by edges. All the qubits are initially prepared in the so-called $\ket{+}$ state. All the
qubits are entangled using controlled-Z (CZ) operations between every pair of qubits that have an
edge in the original graph. In our work, we restrict our study to graph states.
In this thesis, we discuss our contribution of quantum information processing protocols using graph
states that includes:
1) Recovery from a quantum erasure: We consider the problem of a node failure occurring in a
network modeled by a graph. By describing the loss of a qubit due to the failure of a node as a
quantum erasure, we present a recovery mechanism for distributed quantum information using
purification followed by an error correction procedure.
2) Eavesdropping on the graph state: An eavesdropper uses probe qubits and entangles them with
the qubits of the graph state via unitary operations. Following the unitary interaction, the
eavesdropper performs measurement on the probe qubits. We investigate the behavior of mutual
information between the source and the eavesdropper and that between the source and the
destination. We define the disturbance caused to the original graph state and study the efficacy of
entanglement. We also come up with a scheme to detect the presence of the eavesdropper and
recover from the disturbance caused to the graph state using ideas from coding theory.
3) Quantum channels on a graph state: Measurement based quantum computing is an alternative
way of quantum information processing that describes the unitary evolution of a quantum state
using the cluster state and well-defined measurements.
We use the measurement based quantum computing (MBQC) formalism to describe memoryless
quantum channels between any two nodes of a network and also come up with the expressions of
the capacity of transmission. | en_US |
dc.language.iso | en_US | en_US |
dc.relation.ispartofseries | ;G29838 | |
dc.rights | I grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part
of this thesis or dissertation | en_US |
dc.subject | measurement based quantum computing | en_US |
dc.subject | superdense coding | en_US |
dc.subject | quantum teleportation | en_US |
dc.subject | Eavesdropping on the graph state | en_US |
dc.subject | Quantum channels on a graph state | en_US |
dc.subject.classification | Research Subject Categories::TECHNOLOGY::Electrical engineering, electronics and photonics::Electronics | en_US |
dc.title | Protocols for quantum information processing on graph states | en_US |
dc.type | Thesis | en_US |
dc.degree.name | PhD | en_US |
dc.degree.level | Doctoral | en_US |
dc.degree.grantor | Indian Institute of Science | en_US |
dc.degree.discipline | Engineering | en_US |