We consider a system of multiple qubits without any quantum control. We show that one can mediate entanglement between different subsystems in a controlled way by adding a (locally) controlled auxiliary system of the same size that couples via an always-on, distant dependent interaction to the system qubits. Solely by changing the internal state of the control system, one can selectively couple it to selected qubits, and ultimately generate different kinds of entanglement within the system. This provides an alternative way for quantum control and quantum gates that does not rely on the ability to switch interactions on and off at will, and can serve as a locally controlled quantum switch where all entanglement patterns can be created. We demonstrate that such an approach also offers an increased error tolerance w.r.t. position fluctuations.
 F. Albertini and D. D’Alessandro, Syst. Control. Lett. 151, 104913 (2021).
 M. Hein, W. Dür, J. Eisert, R. Raussendorf, M. Van den Nest, and H.-J. Briegel, arXiv:quant-ph/0602096 (2006).
 M. K. Joshi, A. Elben, B. Vermersch, T. Brydges, C. Maier, P. Zoller, R. Blatt, and C. F. Roos, Phys. Rev. Lett. 124, 240505 (2020).
 P. Sekatski, S. Wölk, and W. Dür, Phys. Rev. Research 2, 023052 (2020).
 B. Kraus, Phys. Rev. Lett. 104, 020504 (2010a).
 E. T. Campbell and S. C. Benjamin, Phys. Rev. Lett. 101, 130502 (2008).
 D. Gottesman, Stabilizer codes and quantum error correction, arXiv:quant-ph/9705052 (1997).
 T. Coopmans, R. Knegjens, A. Dahlberg, D. Maier, L. Nijsten, J. de Oliveira Filho, M. Papendrecht, J. Rabbie, F. Rozpędek, M. Skrzypczyk, et al., Commun. Phys. 4, 1 (2021).
 F. Riera-Sàbat, P. Sekatski, and W. Dür, In preparation.
 Ferran Riera-Sàbat, Pavel Sekatski, and Wolfgang Dür, "A quantum simulator based on locally controlled logical systems", New Journal of Physics 25 2, 023001 (2023).
The above citations are from Crossref's cited-by service (last updated successfully 2023-12-07 04:16:04) and SAO/NASA ADS (last updated successfully 2023-12-07 04:16:05). The list may be incomplete as not all publishers provide suitable and complete citation data.
This Paper is published in Quantum under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Copyright remains with the original copyright holders such as the authors or their institutions.