Spring 2025

Abstract: Moire superlattices in semiconductors are predicted to exhibit a rich variety of interaction-induced topological states. However, experimental demonstrations of such topological states, apart from MoTe2 superlattices [1–8], have remained scarce [9, 10]. Here, we report the first optical detection of quantum anomalous Hall (QAH) states in twisted WSe2 homobilayer (tWSe2).

Abstract: While trapped ions are well-developed technologies for both quantum computation and simulation, incorporating them into nodes of a quantum network typically requires quantum frequency conversion (QFC). QFC extends the network's operating range given that most atomic ions emit polarization-entangled photons in the visible or near-infrared wavelengths.We demonstrate two-stage, polarization-preserving QFC for shifting Ba+ single photons upwards of 375 THz to the telecom O-band for quantum networking.

Recently, an experiment using a quantum processor realized a protocol for ‘Certified Randomness’, generating remotely verifiable randomness appealing for applications involving mutually untrusting parties. This protocol builds on the success of pushing the ability of quantum computers to perform beyond-classical computational tasks and leverages the classical hardness of sampling from random quantum circuits to certify 70 kbits of entropy against a realistic adversary using best-known attacks.

JQI is hosting it's fourth annual World Quantum Day AMA. Join us on r/AskScience with your questions!

Our post is available here: https://www.reddit.com/r/askscience/comments/1jywddb/askscience_ama_series_we_are_quantum_scientists/.

There has been increasing interest in classifying mixed quantum states with topological order, particularly in understanding when states connected by local noise channels remain in the same topological phase. This framework has recently been applied to topological quantum error-correcting codes, where the use of the Petz recovery map has shown that phase transitions in mixed states align with the decodability threshold of these codes. Motivated by these insights, we introduce a scalable, parallelized, quasi-local decoder that achieves near-optimal performance for topological codes.

Abstract: There has been increasing interest in classifying mixed quantum states with topological order, particularly in understanding when states connected by local noise channels remain in the same topological phase. This framework has recently been applied to topological quantum error-correcting codes, where the use of the Petz recovery map has shown that phase transitions in mixed states align with the decodability threshold of these codes.

Building large-scale modular quantum computers and quantum networks require high fidelity, high efficiency, and long lifetime quantum memories [1]. Quantum memories are proposed to increase photon-mediatated matter-qubit entanglment rates by synchronizing photon interference between network nodes [2]. Hybrid quantum networking leverages trapped ions’ high fidelity operations and neutral-atoms’ single photon manipulation for increased entanglement rates over single-species quantum networks [3-8].

Abstract: Building large-scale modular quantum computers and quantum networks require high fidelity, high efficiency, and long lifetime quantum memories [1]. Quantum memories are proposed to increase photon-mediatated matter-qubit entanglment rates by synchronizing photon interference between network nodes [2].

Abstract: Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where non-local fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is however challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers.

Abstract: In this talk, we will mainly focus on noisy quantum trees: at each node of a tree, a received qubit unitarily interacts with fresh ancilla qubits, after which each qubit is sent through a noisy channel to a different node in the next level. Therefore, as the tree depth grows, there is a competition between the irreversible effect of noise and the protection against such noise achieved by delocalization of information.