Abstract
Preparing large-scale multi-partite entangled states of quantum bits in each physical form such as photons, atoms or electrons for each specific application area is a fundamental issue in quantum science and technologies. Here, we propose a setup based on Pauli spin blockade (PSB) for the preparation of large-scale W states of electrons in a double quantum dot (DQD). Within the proposed scheme, two W states of n and m electrons respectively can be fused by allowing each W state to transfer a single electron to each quantum dot. The presence or absence of PSB then determines whether the two states have fused or not, leading to the creation of a W state of n + m − 2 electrons in the successful case. Contrary to previous works based on quantum dots or nitrogen-vacancy centers in diamond, our proposal does not require any photon assistance. Therefore the ‘complex’ integration and tuning of an optical cavity is not a necessary prerequisite. We also show how to improve the success rate in our setup. Because requirements are based on currently available technology and well-known sensing techniques, our scheme can directly contribute to the advances in quantum technologies and, in particular in solid state systems.
Highlights
The preparation and manipulation of entangled systems is crucial for quantum technologies and more precisely, for quantum information
In this work, considering spin of electrons in a double quantum dot (DQD) system, we propose a setup utilising the Pauli spin blockade (PSB) as a key element to fuse W states in a DQD system
We should mention that the previous discussion concerns the possibility of implementing the fusion process with currently available technology only, and not the way of storing a multipartite entangled state in a quantum memory which is itself a separate problem
Summary
The preparation and manipulation of entangled systems is crucial for quantum technologies and more precisely, for quantum information. First proposed and further improved for polarization-based encoded photons[3,4,5,6,7,8,9,10,11,12], these approaches have been considered for electronic W states too, requiring atom-cavity interactions[13,14,15,16,17,18], and followed by different generation approaches, e.g., using quantum eraser and[19], spin torque[20], parity check gates[21] and so on on[22,23] Solid state systems such as quantum dots and nitrogen-vacancy centers in diamond have been considered for preparing W states of photonic qubits, as well as electronic qubits[24,25,26]. We denote Wn A and Wm B the W states of two parties A and B and n and m their respective number of electrons, so we have:
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