Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
The magnetic properties of ceramic samples of Gd1.98R0.02CuO4 R= Ca Sr Th were studied and compared with Gd2CuO4. The results showed weak ferromagnetic ordering in all samples. We observed two magnetic ordering temperatures in the heat capacity measurement a sharp peak at TN(Gd) 6.5 K that can be attributed to the Neel temperature of Gd3+ ions and the second transition temperature at about 20 K that suggested to the magnetic interactions of Gd-Cu. The third anomaly was seen at TN(Cu)=280 K in susceptibility measurements.
Epitaxial MnSi grown on Si (111) offers new opportunities in the development of spin-dependent transport in helical magnets. Helical magnets are a class of noncollinear structures that have shown promise as a material for spin-dependent electron transport studies.The helical magnets are of particular interest in spintronics because in these magnets the electron spins spiral about a particular crystallographic direction, this property can allow for control over electron spin.
Pb2CrO5 have received considerable interests due to their potentials applications in UV radiation measuring devices, visible and UV light photodetectors. In this research we are examining the structural, electronic, magnetic, and thermal properties of polycrystalline Pb2-xLaxCrO5. Samples have been prepared using a solid state solution technique. The temperature dependent magnetic measurements reveal a transition in the Pb2CrO5 and La doped samples near 300 K.
Heavy-hole spin states have been proposed as a robust qubit candidate. Nevertheless, the coupling of the hole spins to nuclei in the surrounding medium likely limits hole-spin coherence and has, until very recently, been overlooked. We describe the spin decoherence of a heavy-hole in a semiconductor quantum dot, subject to spin echo pulses. We do so both analytically and numerically for an experimentally realistic number (10^4) of nuclear spins.
Quantum Key Distribution is a form of public-key cryptography where the security comes from the unique properties of quantum mechanical systems: entanglement and the no-cloning theorem, rather than computational complexity. With increased adoption of fibre optic networks, it may be possible to implement QKD in parallel with classical data traffic. Many research projects have demonstrated QKD over fibre optic networks at the same wavelengths as existing network traffic.
Development of quantum computing promises, among other things, improvement of scientific computation performance. Indeed, a computer exploiting the proprieties of quantum mechanics would allow for computation power exponentially greater than a classic computer.We develop double lateral quantum dots with micro-magnets to control spin orientation of electrostatically confined electrons. In this talk, an introduction to the mechanisms used in the spin control will be given. Then, methods used to characterize the micro-magnets will be described.
A quantum computer is a computer fabricated using quantum bits (qubits) that uses the quantum properties of matter (entanglement, superposition of states, etc.). Such a computer would allow certain calculations to be done exponentially more quickly than with a classical computer. An electron in a quantum box constitutes a perfect two-level system and can thus be used as a qubit. In my talk, I will give an introduction to lateral quantum dots, their fabrication process and how they can be used as qubits.
TBA
Quantum entanglement is a valuable resource in the field of quantum information science and allows one to accomplish many information processing tasks. In quantum transformations an entangled state A can be converted to another state B through local operations assisted by classical communication (LOCC). It has also been demonstrated that there exist entangled states A, B, C such that state A cannot be converted to a state B, but A otimes C can be converted to B otimes C by LOCC, where C is a suitably chosen entangled state acting as the catalyst.
Thermodynamics is, at heart, a probabilistic theory about the state of physical systems. Traditionally, however, our knowledge of systems is modelled implicitly: for instance, it is often assumed that we only have access to a few macroscopic parameters, like the temperature, energy, or volume of a gas, and that all states satisfying those parameters are equally likely.