Use quantum dots as a single electron emission source at will

Physicists at the Paris Pedagogical University (Ecole Normale Supérieure), France, have just reached an important jump in building quantum computers from confusing electrons.

The study, published in the journal Science , has shown that small regions in semiconductors called quantum dots can allow electron emission in the nanosecond time scale (ns). overcoming current active electronic components ( see details on Science 316 (2007) 1172 ).

Current computers process information by performing arithmetic operations on binary counting systems, with bits 0 and 1. The quantum computer being studied uses the messy phenomenon to create quantum bits (called qubits), can be simultaneously in both bits 0 and 1 at the same time. Quantum computers promise the ability to process information at an extremely fast speed while handling a much larger amount of information and work than today's computers.

The group's new research, led by Christian Glattli (at the Paris University of Education, France) and colleagues at several other French agencies, has made an important jump to the ability to build qubits. from 2-dimensional imprisoned electrons in semiconductors (called 2-dimensional electron gas 2DEG). From a GaAs semiconductor wafer, they doped and created a quantum dot at the top of the plate and a set of two-dimensional electron gas at the other end with a barrier between them. By placing a rapidly changing voltage across the quantum dot and a constant voltage across the barrier, they can translate the energy levels of the electron into the quantum dot so that the electron can enter or exit. exit 2-way electronic gas system at the other end.

The principle diagram of the system and results are summarized (According to Science 316 (2007) 1172 ).

In fact, quantum dots have been used as a single electronic source before, but the components of this group are the first to allow radiation and electron absorption at intervals of only a few nanoseconds, creating The speed of components is quite compatible with current electronic circuits. The system of the group is said to be quantum dots and port components are equivalent as a resistor and capacitor in series, and they use the principle of RC circuit to calculate the total impedance in quantum circuit - gate , and therefore electronically emitted from quantum dots is calculated from the voltage applied to the system.

In order to create real qubits, Glattli's team will need to prove that two individual sources of electrons can produce combined electrons and subsequent disturbing states can be kept for longer periods of time. micro seconds - according to Stephen Giblin, a solid physicist.

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