Dmitry Kravchenko

Nonlocal quantum XOR games for large number of players

Nonlocal games are used to display differences between classical and quantum world In this paper, we study nonlocal games with a large number of players We give simple methods for calculating the classical and the quantum values for symmetric XOR games with one-bit input per player, a subclass of nonlocal games We illustrate those methods on the example of the N-player game (due to Ardehali [Ard92]) that provides the maximum quantum-over-classical advantage.

Advantage of Quantum Strategies in Random Symmetric XOR Games

Non-local games are known as a simple but useful model which is widely used for displaying nonlocal properties of quantum mechanics. In this paper we concentrate on a simple subset of non-local games: multiplayer XOR games with 1-bit inputs and 1-bit outputs which are symmetric w.r.t. permutations of players.

Grover's Search with Faults on Some Marked Elements

Grovers algorithm is a quantum query algorithm solving the unstructured search problem of size N using

Quantum versus Classical Online Algorithms with Advice and Logarithmic Space.

O\sqrt{N}

Grover’s Search with Faults on Some Marked Elements

queries. It provides a significant speed-up over any classical algorithm [2]. The running time of the algorithm, however, is very sensitive to errors in queries. Multiple authors have analysed the algorithm using different models of query errors and showed the loss of quantum speed-up [1, 4]. We study the behavior of Grovers algorithm in the model where the search space contains both faulty and non-faulty marked elements. We show that in this setting it is indeed possible to find one of marked elements in

Parity Oblivious d-Level Random Access Codes and Class of Noncontextuality Inequalities.

O\sqrt{N}