Generalized Fock Spaces and New Forms of Quantum Statistics

The recent discoveries of new forms of quantum statistics require a close look at the under-lying Fock space structure. This exercise becomes all the more important in order to provide a general classification scheme for various forms of statistics, and establish interconnections among them whenever it is possible. We formulate a theory of generalized Fock spaces, which has a three tired structure consisting of Fock space, statistics and algebra. This general formalism unifies various forms of statistics and algebras, which were earlier considered to describe different systems. Besides, the formalism allows us to construct many new kinds of quantum statistics and the associated algebras of creation and destruction operators. Some of these are: orthostatistics, null statistics or statistics of frozen order, quantum group based statistics and its many avatars, and `doubly-infinite' statistics. The emergence of new forms of quantum statistics for particles interacting with singular potential is also highlighted.Comment: 9 pages, LaTex, Appeared in Spin-Statistics Connection and Commutation Relations, edited by R.C. Hilborn and G.M. Tino, (American Institute of Physics, NY, 2000) p. 16

Fock Space Representation of Differential Calculus on the Noncommutative Quantum Space

A complete Fock space representation of the covariant differential calculus on quantum space is constructed. The consistency criteria for the ensuing algebraic structure, mapping to the canonical fermions and bosons and the consequences of the new algebra for the statistics of quanta are analyzed and discussed. The concept of statistical transmutation between bosons and fermions is introduced

Sum Throughput Maximization in Multi-Tag Backscattering to Multiantenna Reader

Backscatter communication (BSC) is being realized as the core technology for pervasive sustainable Internet-of-Things applications. However, owing to the resource-limitations of passive tags, the efficient usage of multiple antennas at the reader is essential for both downlink excitation and uplink detection. This work targets at maximizing the achievable sum-backscattered-throughput by jointly optimizing the transceiver (TRX) design at the reader and backscattering coefficients (BC) at the tags. Since, this joint problem is nonconvex, we first present individually-optimal designs for the TRX and BC. We show that with precoder and {combiner} designs at the reader respectively targeting downlink energy beamforming and uplink Wiener filtering operations, the BC optimization at tags can be reduced to a binary power control problem. Next, the asymptotically-optimal joint-TRX-BC designs are proposed for both low and high signal-to-noise-ratio regimes. Based on these developments, an iterative low-complexity algorithm is proposed to yield an efficient jointly-suboptimal design. Thereafter, we discuss the practical utility of the proposed designs to other application settings like wireless powered communication networks and BSC with imperfect channel state information. Lastly, selected numerical results, validating the analysis and shedding novel insights, demonstrate that the proposed designs can yield significant enhancement in the sum-backscattered throughput over existing benchmarks.Comment: 17 pages, 5 figures, accepted for publication in IEEE Transactions on Communication

Wavelet-Based Compressive Sensing for Point Scatterers

Compressive Sensing (CS) allows for the sam-pling of signals at well below the Nyquist rate but does so, usually, at the cost of the suppression of lower amplitude sig-nal components. Recent work suggests that important infor-mation essential for recognizing targets in the radar context is contained in the side-lobes as well, which are often sup-pressed by CS. In this paper we extend existing techniques and introduce new techniques both for improving the accu-racy of CS reconstructions and for improving the separa-bility of scenes reconstructed using CS. We investigate the Discrete Wavelet Transform (DWT), and show how the use of the DWT as a representation basis may improve the accu-racy of reconstruction generally. Moreover, we introduce the concept of using multiple wavelet-based reconstructions of a scene, given only a single physical observation, to derive re-constructions that surpass even the best wavelet-based CS reconstructions. Lastly, we specifically consider the effect of the wavelet-based reconstruction on classification. This is done indirectly by comparing outputs of different algo-rithms using a variety of separability measures. We show that various wavelet-based CS reconstructions are substan-tially better than conventional CS approaches at inducing (or preserving) separability, and hence may be more useful in classification applications

Labour Demand and Labour-saving Options: A Case of Groundnut Crop in India

Groundnut is a labour-intensive crop, especially for operations like sowing, weeding, harvesting, and drying. But, of-late, due to timely unavailability of labour, many farmers are not able to exercise timely operations resulting in low yield realization. The present study conducted in two major groundnut-growing states, viz. Gujarat and Andhra Pradesh, has revealed that farmers employ more human labour in weeding and harvesting operations in groundnut than in other operations. The practise of manual decortication and stripping is followed by a larger number of farmers in Andhra Pradesh than in Gujarat, indicating less mechanization in the former. For weeding, though, the human labour-use in weedicide + bullock intercultivation + hand weeding technique is almost half of that of the bullock inter-cultivation + hand weeding, only 13 per cent of the farmers practise this labour-saving technique and hence this method should be disseminated in both the regions to reduce human-labour demand. In Andhra Pradesh, for all the operations in groundnut cultivation except harvesting, the cost as well as labour-use has been reduced substantially due to use of partial/complete mechanization methods. Hence, the necessary infrastructure (labour-saving machineries) should be created at the village or block level to reduce the human-labour demand.Labour demand, Groundnut cultivation, Labour-saving techniques, Agricultural and Food Policy, J23, J21,