HypIR: Hypertext Based Information Retrieval

Information Retrieval (IR), which is also known as text or document retrieval, is the process of locating and retrieving docri)nents that are relevant to the user queries. In hypertext environments, docuinent databases are organized as a network of nodes which are interconnected by various types of links. This study introduces a hypertext-based text retrieval system, HypIR. In HypIR, the sentantic relationships ainong docuinents are obtained using a clustering algorithm. A new approach providing the advantages of system maps and history list is introduced to prevent the user fiotn being lost in the IR hivperspace. The paper presents the underlying concepts and iinplementation details. HypIR is based on the object-oriented paradigm and its execution platforin is HyperCard

Experimentally reducing the quantum measurement back-action in work distributions by a collective measurement

In quantum thermodynamics, the standard approach to estimate work fluctuations in unitary processes is based on two projective measurements, one performed at the beginning of the process and one at the end. The first measurement destroys any initial coherence in the energy basis, thus preventing later interference effects. In order to decrease this back-action, a scheme based on collective measurements has been proposed in~[PRL 118, 070601 (2017)]. Here, we report its experimental implementation in an optical system. The experiment consists of a deterministic collective measurement on identically prepared two qubits, encoded in the polarisation and path degree of a single photon. The standard two projective measurement approach is also experimentally realized for comparison. Our results show the potential of collective schemes to decrease the back-action of projective measurements, and capture subtle effects arising from quantum coherence.Comment: 9 pages, 4 figure