Quantum mechanics is at the heart of our technology and economy - the laser and the transistor are quantum devices - but its full potential is far from being realized. Recent technological advances in optics, nanoscience and engineering allow experimentalists to create artificial structures or put microscopic and mesoscopic systems under new manipulable conditions in which quantum phenomena play a fundamental role.

Quantum technologies exploit these effects with practical purposes. The objective of Quantum Science is to discover, study, and control quantum efects at a fundamental level. These are two sides of a virtuous circle: new technologies lead to the discovery and study of new phenomena that will lead to new technologies.

Our group's aim is  to control and understand quantum phenomena in a multidisciplinary intersection of  Quantum Information, Quantum optics and cold atoms, Quantum Control, Spintronics, Quantum metrology, Atom interferometry, Superconducting qubits and Circuit QED and Foundations of Quantum Mechanics.



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Adam Mickiewicz University, Poznan, Poland (Seminar)

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Place: Seminar room, Theoretical Physics

Time: 15:00

TITLE: Introduction to quantum state tomography

SPEAKER: Adam Miranowicz

AFFILIATION: Adam Mickiewicz University,  Poznan,  Poland


Quantum state tomography (QST) is a method of determining an
unknown quantum state (density matrix) in a series of measurements
on multiple copies of the state. QST is an essential tool for the
verification and benchmarking of quantum devices used, e.g., for
quantum state engineering, quantum communication, and quantum
information processing.

I will discuss how to implement a few optimal methods of QST for
(i) polarization states of two photons [1] and (ii) solid-state
systems with a large nuclear spin I = 3/2 in nanometer-scale
semiconductors devices based on a quantum well [2]. I will also
report a recent optical experimental implementation of an optimal
QST [3].


[1] A. Miranowicz, K. Bartkiewicz, J. Perina Jr., M. Koashi, N.
Imoto, and F. Nori: Optimal two-qubit tomography based on local
and global measurements: Maximal robustness against errors as
described by condition numbers, Phys. Rev. A 90, 062123 (2014).

[2] A. Miranowicz, S.K. ÷zdemir, J. Bajer, G. Yusa, N. Imoto, Y.
Hirayama, F. Nori: Quantum state tomography of large nuclear spins
in a semiconductor quantum well: Optimal robustness against errors
as quantified by condition numbers, Phys. Rev. B 92, 075312

[3] K. Bartkiewicz, A. »ernoch, K. Lemr, A. Miranowicz: Priority
Choice Experimental Two-qubit Tomography: Measuring One by One All
Elements of Density Matrices, e-print arXiv:1506.01317