Learn More
  • Pranab Sen
  • 2012
We construct an encoding and decoding scheme achieving the Chong-Motani-Garg inner bound [1] for a two sender two receiver interference channel with classical input and quantum output. This automatically gives a similar inner bound for sending classical information through an interference channel with quantum inputs and outputs without entanglement(More)
We give efficient quantum algorithms for the problems of <sc>Hidden Translation</sc> and <sc>Hidden Subgroup</sc> in a large class of non-abelian groups including solvable groups of constant exponent and of constant length derived series. Our algorithms are recursive. For the base case, we solve efficiently <sc>Hidden Translation</sc> in Z(More)
Calculating the capacity of interference channels is a notorious open problem in classical information theory. Such channels have two senders and two receivers, and each sender would like to communicate with a partner receiver. The capacity of such channels is known exactly in the settings of &#x201C;very strong&#x201D; and &#x201C;strong&#x201D;(More)
We show lower bounds in the multi-party quantum communication complexity model. In this model, there are t parties where the ith party has input X i ⊆ [n]. These parties communicate with each other by transmitting qubits to determine with high probability the value of some function F of their combined input (X 1 ,. .. , X t). We consider the class of(More)
We consider the problem of computing the second elementary symmetric polynomial S 2 n (X) ∆ = 1≤i<j≤n X i X j using depth-three arithmetic circuits of the form r i=1 s i j=1 L ij (X), where each L ij is a linear form in X 1 ,. .. , X n. We consider this problem over several fields and determine exactly the number of multiplication gates required. The lower(More)
It has been known for some time that graph isomorphism reduces to the hidden subgroup problem (HSP). What is more, most exponential speedups in quantum computation are obtained by solving instances of the HSP. A common feature of the resulting algorithms is the use of quantum coset states, which encode the hidden subgroup. An open question has been how hard(More)
We prove lower bounds for the direct sum problem for two-party bounded error randomised multiple-round communication protocols. Our proofs use the notion of information cost of a protocol, as defined by Chakrabarti et al. [CSWY01] and refined further by Bar-Yossef et al. [BJKS02]. Our main technical result is a 'compression' theorem saying that, for any(More)
We consider a fundamental problem in data structures, static predecessor searching: Given a subset S of size n from the universe [m], store S so that queries of the form " What is the predecessor of x in S? " can be answered efficiently. We study this problem in the cell probe model introduced by Yao [Yao81]. Recently, Beame and Fich [BF99] obtained optimal(More)
This paper presents reconfigurable RF integrated circuits (ICs) for a compact implementation of an intelligent RF front-end for multiband and multistandard applications. Reconfigurability has been addressed at each level starting from the basic elements to the RF blocks and the overall front-end architecture. An active resistor tunable from 400 to 1600 /spl(More)