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A measurement strategy is described that is able to read out the parity of minimal two-site Kitaev chains in real time, by coupling two Majoranas and resolving their quantum capacitance.

The authors realize two- and three-site Kitaev chains in semiconducting quantum dots coupled via superconductors and tune them to the sweet spot where zero-energy Majorana modes appear at the chain ends. To assess Majorana localization, they couple the system to an additional quantum dot.

In a step towards topological quantum computation, a quantized Majorana conductance has been demonstrated for a semiconducting nanowire coupled to a superconductor.

Single-photon sources are important for quantum optical technologies, although achieving efficient light extraction from them with waveguides is limited in top-down approaches. Reimeret al. show a high extraction efficiency using a bottom-up method to grow quantum dots on the axis of nanowire waveguides.

Nanowires with sharp interfaces between two different semiconducting materials could lead to useful nanoelectronic and nanophotonic structures. Hocevar et al.develop a method to integrate a gallium arsenide section in silicon nanowires with atomically sharp interfaces and no dislocations.

Disorder has been a prime challenge to study the topological properties in a hybrid system. Here, Zhanget al. report ballistic superconductivity in InSb nanowires interfacing with a NbTiN superconductor, paving the way for disorder-free Majorana devices.

Understanding the ground state (GS) phase transitions in the quantum tunneling regime of a superconducting system is important for future qubit devices. Here, Shen, Heedt and Borsoi et al. report distinct types of fermion parity GS transitions as a function of magnetic field and gate voltages in a Coulomb-blockaded InSb–Al island.

Measuring the transmission phase of a quantum dot is crucial for the read-out of future topological qubits based on nanowire networks but has not been established yet. Here, the authors demonstrate interferometric read-out of the transmission phase in a nanowire-based architecture.

Andreev bound states in semiconductor–superconductor hybrid structures are studied using microwave spectroscopy — a tool that could be also used for investigating Majorana modes.

InSb nanowire crosses, which could be used for braiding Majorana modes, are synthesized using a technique that allows two growing nanowires to merge.

A transmon qubit insensitive to magnetic fields is a crucial element in topological quantum computing. Here, Kroll et al. create graphene transmons by integrating monolayer graphene Josephson junctions into microwave frequency superconducting circuits, allowing them to operate in a parallel magnetic field of 1 T.

The proximity effect in semiconductor-superconductor nanowires is expected to generate an induced gap in the semiconductor. Here, the authors study the superconducting proximity effect in InSb nanowires with an Al/Pt shell, demonstrating control of the induced gap using electric and magnetic fields.

A Kitaev chain formed by two quantum dots coupled via a superconductor support the so-called poor man’s Majorana bound states. Here, the authors form a minimal Kitaev chain using Yu-Shiba-Rusinov states and show that the resulting bound states are more robust than in the case of unproximitized quantum dots.

One minute parity lifetimes are reported in a superconducting transistor made of niobium titanite nitride coupled to aluminium contacts even in the presence of small magnetic fields, enabling the braiding of Majorana bound states.

Researchers investigate the internal gain of InAsP quantum dots embedded in an InP nanowire by performing photocurrent measurements down to the single-photon regime. The resulting gain ( > 10⁴) is a significant step towards single-shot electrical read-out of an exciton qubit state for the transfer of quantum information between flying and stationary qubits.

A minimal artificial Kitaev chain can be realized by using two spin-polarized quantum dots in an InSb nanowire strongly coupled by both elastic co-tunnelling and crossed Andreev reflection.

A three-site Kitaev chain, constructed from three semiconducting quantum dots coupled by superconducting segments in a hybrid InSb/Al nanowire, shows enhanced robustness of edge zero-energy modes against variations in the coupling strengths or electrochemical potentials compared with a chain containing only two quantum dots.

The bandgap of a low-disorder, bent carbon nanotube is exploited to achieve Pauli blockade and spin resonance.

This paper reports a study of supercurrents through a quantum dot created in a semiconductor nanowire by local electrostatic gating. Owing to strong Coulomb interaction, electrons only tunnel one-by-one through the discrete energy levels of the quantum dot. This, nevertheless, can yield a supercurrent when subsequent tunnel events are coherent.

Topological superconductivity, a state that can support the formation of Majorana zero modes, can be induced in the edge state of a InAs/GaSb nanowire.

The hybrid architecture of Andreev spin qubits made using semiconductor–superconductor nanowires means that supercurrents can be used to inductively couple qubits over long distances.

Nanowire devices exhibiting ballistic transport show characteristics of Majorana modes, ruling out alternative explanations other than topological superconductivity.

Andreev bound states can form in hybrid semiconducting-superconducting devices and can mirror the experimental signatures of the much sought topologically non-trivial Majorana bound states. Here, van Driel, Wang and coauthors present a method of directly measuring the spin-polarized excitation spectrum of Andreev bound states.

Quantum interference between two indistinguishable surface plasmons is demonstrated in a nanoscale plasmonic circuit.

Topological matter can host low-energy quasiparticles, which, in a superconductor, are Majorana fermions described by a real wavefunction. The absence of complex phases provides protection for quantum computations based on topological superconductivity.

Tunneling spectroscopy is widely used to examine the subgap spectra in semiconductor/superconductor nanostructures. Here, the authors develop an alternative type of tunnel probe for InSb-Al hybrid nanowires, enabling study of the spatial extension of Andreev bound states.

Semiconductor qubits can benefit from existing industrial methods, but there are challenges in coupling qubits together. A hybrid superconductor–semiconductor qubit that couples to superconducting qubit devices may overcome these issues.

Controllable detection of singlet and triplet Cooper pair splitting via crossed Andreev reflection is demonstrated in spin-polarized quantum dots on a superconducting nanowire platform with strong spin–orbit coupling.

Advanced fabrication techniques enable a wide range of quantum devices, such as the realization of a topological qubit. Here, the authors introduce an on-chip fabrication technique based on shadow walls to implement topological qubits in an InSb nanowire without fabrication steps such as lithography and etching.

The interplay of induced superconductivity and magnetic fields should drive InAs nanowires into a topological superconducting phase. Laroche et al. use the microwave radiation emitted by an InAs nanowire Josephson junction to observe the 4π-periodic Josephson effect, a hallmark of the topological phase.

The pursuit of topological qubits based on Majorana zero mode within nanowires is highly desired. Here, Zhang et al. summarize the current achievements and discuss the opportunities and challenges of several key next-step experiments.

Both sound and heat are carried through solids by phonons. In the world of nanoscale objects, the minimum amount of heat or sound that can flow is limited by the laws of quantum mechanics.

A finely tuned growth strategy to generate nanowire networks that fulfil all the prerequisites for braiding may lead to a demonstration of Majorana braiding.

Indium-Antimonide (InSb) possesses specific properties that makes it a suitable candidate for realizing Majorana-based topological quantum computers. The authors describe a method to fabricate single crystalline InSb nanowire networks from single nuclei enabling them to realize high-quality quantum transport in their devices.

Topological Majorana bound states have potential for encoding, manipulating and protecting quantum information in condensed-matter systems. This Review discusses emergence and characterization of Majorana bound states in realistic devices based on hybrid semiconducting nanowires and their connection to more conventional Andreev bound states.

A wealth of physics can be explored by connecting two superconducting electrodes to a quantum dot. This article reviews the different electron-transport regimes observed in such devices and possible applications.