An exploration of societal impacts of quantum technology: Towards responsible quantum innovation

The rapid advancement of quantum computing and communication (QCC) technologies promises transformative benefits for companies, yet also poses ethical and societal challenges reminiscent of historical technological introductions. This study addresses the Collingridge Dilemma, which posits that controlling technology becomes increasingly...

Influence of coherence time drift on the secret key rate

Quantum communication provides a plethora of new possibilities compared to the realm of classical communication. Since the channels used are noisy, losses are unavoidable, and quantum repeaters are needed to transmit a signal over longer distances to overcome these exponential losses. To increase the performance of these repeaters, cutoff times...

Towards European standards for quantum technologies

The Second Quantum Revolution facilitates the engineering of new classes of sensors, communication technologies, and computers with unprecedented capabilities. Supply chains for quantum technologies are emerging, some focused on commercially available components for enabling technologies and/or quantum-technologies research infrastructures,...

Efficient Optimization of Cutoffs in Quantum Repeater Chains

Quantum communication enables the implementation of tasks that are unachievable with classical resources. However, losses on the communication channel preclude the direct long-distance transmission of quantum information in many relevant scenarios. In principle, quantum repeaters allow one to overcome losses. However, realistic hardware...

Efficient computation of the waiting time and fidelity in quantum repeater chains

Quantum communication enables a host of applications that cannot be achieved by classical communication means, with provably secure communication as one of the prime examples. The distance that quantum communication schemes can cover via direct communication is fundamentally limited by losses on the communication channel. By means of quantum...

Building blocks of quantum repeater networks

Characterization of depolarizing channels using two-photon interference

Depolarization is one of the most important sources of error in a quantum communication link that can be introduced by the quantum channel. Even though standard quantum process tomography can, in theory, be applied to characterize this effect, in most real-world implementations depolarization cannot be distinguished from time-varying unitary...

Proposal for a transmon-based quantum router

We propose an implementation of a quantum router for microwave photons in a superconducting qubit architecture consisting of a transmon qubit, SQUIDs and a nonlinear capacitor. We model and analyze the dynamics of operation of the quantum switch using quantum Langevin equations in a scattering approach and compute the photon reflection and...