Efficient Quantum State Tomography for Quantum Information Processing using a two-dimensional Fourier Transform Technique

A new method of quantum state tomography for quantum information processing is described. The method based on two-dimensional Fourier transform technique involves detection of all the off-diagonal elements of the density matrix in a two-dimensional experiment. All the diagonal elements are detected in another one-dimensional experiment. The method is efficient and applicable to a wide range of spin systems. The proposed method is explained using a 2 qubit system and demonstrated by tomographing arbitrary complex density matrices of 2 and 4 qubit systems using simulations.Comment: 11 pages and 2 figure

NMR investigation of contextuality in a quantum harmonic oscillator via pseudospin mapping

Physical potentials are routinely approximated to harmonic potentials so as to analytically solve the system dynamics. Often it is important to know when a quantum harmonic oscillator (QHO) behaves quantum mechanically and when classically. Recently Su et. al. [Phys. Rev. A {\bf 85}, 052126 (2012)] have theoretically shown that QHO exhibits quantum contextuality (QC) for a certain set of pseudospin observables. In this work, we encode the four eigenstates of a QHO onto four Zeeman product states of a pair of spin-1/2 nuclei. Using the techniques of NMR quantum information processing, we then demonstrate the violation of a state-dependent inequality arising from the noncontextual hidden variable model, under specific experimental arrangements. We also experimentally demonstrate the violation of a state-independent inequality by thermal equilibrium states of nuclear spins, thereby assessing their quantumness.Comment: 5 Pages, 3 Figures, context dependency illustrated, error below eq. 5 correcte

Simulation of mirror inversion of quantum states in an XY spin chain using NMR

We report an experimental quantum simulation of unitary dynamics of an XY spin chain with pre-engineered couplings. Using this simulation, we demonstrate the mirror inversion of quantum states, proposed by Albanese et al. [Phys. Rev. Lett. 93, 230502 (2004)]. The experiment is performed with a 5-qubit dipolar coupled spin system using nuclear magnetic resonance techniques. To perform quantum simulation we make use of the recently proposed unitary operator decomposition algorithm of Ajoy et al. [Phys. Rev. A 85, 030303 (2012)] along with numerical pulse optimization techniques. Further, using mirror inversion, we demonstrate that entangled states can be transferred from one end of the chain to the other end. The simulations are implemented with high experimental fidelity, which implies that these kind of simulations may be possible in larger systems.Comment: 9 pages, 6 figure

A comparative study between single dose intralesional autologous blood and corticosteroid injection in chronic plantar fasciitis-a short term follow-up study

Background: Plantar fasciitis was initially thought to be an acute inflammatory disease, but histology findings show that it is a chronic degenerative process leading to pain at the calcaneal insertion without any inflammation. The diagnosis of plantar fasciitis is mainly based on clinical symptoms, like heel pain and tightness, and diagnostic imaging is not routinely required. Injection of autologous blood can help stimulate a healing response in chronic tendon disorders. Methods: Radiological imaging of the affected foot in lateral view will be taken. 30 patients will be treated with 2 ml of autologous blood with 1 ml lidocaine and another 30 patients with 2 ml of triamcinolone acetonide with 1 ml lidocaine. The main outcomes measured are subjective based on the visual analog scale done pre-injection, 2 weeks, 4 weeks and 12 weeks post injection. Final outcome was measured based on the pain and activity level at 3 months. Results: The corticosteroid group showed an early sharp and then more gradual improvement in pain scores, but autologous blood group had a steady gradual drop in pain. Conclusions: Autologous whole blood and corticosteroid local injection can both be considered as effective methods in the treatment of chronic plantar fasciitis

Monogamy of quantum correlations reveals frustration in a quantum Ising spin system: Experimental demonstration

We report a nuclear magnetic resonance experiment, which simulates the quantum transverse Ising spin system in a triangular configuration and further show that the monogamy of quantum correlations can be used to distinguish between the frustrated and non-frustrated regimes in the ground state of this system. Adiabatic state preparation methods are used to prepare the ground states of the spin system. We employ two different multipartite quantum correlation measures to analyze the experimental ground state of the system in both the frustrated and non-frustrated regimes. In particular, we use multipartite quantum correlation measures generated by monogamy considerations of negativity, a bipartite entanglement measure, and that of quantum discord, an information-theoretic quantum correlation measure. As expected from theoretical predictions, the experimental data confirm that the non-frustrated regime shows higher multipartite quantum correlations compared to the frustrated one.Comment: Title in the published version is "Multipartite quantum correlations reveal frustration in a quantum Ising spin system", 7 pages, 4 figure