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1. Quantum codes, CFTs, and defects

   https://doi.org/10.1007/JHEP03(2023)017  

   Buican, Matthew; Dymarsky, Anatoly; Radhakrishnan, Rajath (March 2023, Journal of High Energy Physics)

   A<sc>bstract</sc> We give a general construction relating Narain rational conformal field theories (RCFTs) and associated 3d Chern-Simons (CS) theories to quantum stabilizer codes. Starting from an abelian CS theory with a fusion group consisting ofneven-order factors, we map a boundary RCFT to ann-qubit quantum code. When the relevant ’t Hooft anomalies vanish, we can orbifold our RCFTs and describe this gauging at the level of the code. Along the way, we give CFT interpretations of the code subspace and the Hilbert space of qubits while mapping error operations to CFT defect fields. 

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2. Quantum-inspired logic for advanced Transcriptional Programming

   https://doi.org/10.1093/nar/gkaf440  

   Milner, Prasaad_T; Kim, Dowan; Wilson, Corey J. (May 2025, Nucleic Acids Research)

   Abstract The tenets of intelligent biological systems are (i) scalable decision-making, (ii) inheritable memory, and (iii) communication. This study aims to increase the complexity of decision-making operations beyond standard Boolean logic, while minimizing the metabolic burden imposed on the chassis cell. To this end, we present a new platform technology for constructing genetic circuits with multiple OUTPUT gene control using fewer INPUTs relative to conventional genetic circuits. Inspired by principles from quantum computing, we engineered synthetic bidirectional promoters, regulated by synthetic transcription factors, to construct 1-INPUT, 2-OUTPUT logical operations—i.e. biological QUBIT and PAULI-X logic gates—designed as compressed genetic circuits. We then layered said gates to engineer additional quantum-inspired logical operations of increasing complexity—e.g. FEYNMAN and TOFFOLI gates. In addition, we engineered a 2-INPUT, 4-OUTPUT quantum operation to showcase the capacity to utilize the entire permutation INPUT space. Finally, we developed a recombinase-based memory operation to remap the truth table between two disparate logic gates—i.e. converting a QUBIT operation to an antithetical PAULI-X operation in situ. This study introduces a novel and versatile synthetic biology toolkit, which expands the biocomputing capacity of Transcriptional Programming via the development of compressed and scalable multi-INPUT/OUTPUT logical operations. 

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3. Quantum control of spin qubits using nanomagnets

   https://doi.org/10.1038/s42005-022-01041-8  

   Niknam, Mohamad; Chowdhury, Md. Fahim F.; Rajib, Md Mahadi; Misba, Walid Al; Schwartz, Robert N.; Wang, Kang L.; Atulasimha, Jayasimha; Bouchard, Louis-S. (November 2022, Communications Physics)

   Abstract Single-qubit gates are essential components of a universal quantum computer. Without selective addressing of individual qubits, scalable implementation of quantum algorithms is extremely challenging. When the qubits are discrete points or regions on a lattice, selectively addressing magnetic spin qubits at the nanoscale remains a challenge due to the difficulty of localizing and confining a classical divergence-free field to a small volume of space. Herein we propose a technique for addressing spin qubits using voltage-control of nanoscale magnetism, exemplified by the use of voltage control of magnetic anisotropy. We show that by tuning the frequency of the nanomagnet’s electric field drive to the Larmor frequency of the spins confined to a nanoscale volume, and by modulating the phase of the drive, single-qubit quantum gates with fidelities approaching those for fault-tolerant quantum computing can be implemented. Such single-qubit gate operations require only tens of femto-Joules per gate operation and have lossless, purely magnetic field control. Their physical realization is also straightforward using foundry manufacturing techniques. 

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4. Leveraging Hamiltonian simulation techniques to compile operations on bosonic devices

   https://doi.org/10.1088/1751-8121/adb5df  

   Kang, Christopher; Soley, Micheline B; Crane, Eleanor; Girvin, Steven M; Wiebe, Nathan (April 2025, Journal of Physics A: Mathematical and Theoretical)

   Abstract Circuit quantum electrodynamics enables the combined use of qubits and oscillator modes. Despite a variety of available gate sets, many hybrid qubit-boson (i.e. qubit-oscillator) operations are realizable only through optimal control theory, which is oftentimes intractable and uninterpretable. We introduce an analytic approach with rigorously proven error bounds for realizing specific classes of operations via two matrix product formulas commonly used in Hamiltonian simulation, the Lie–Trotter–Suzuki and Baker–Campbell–Hausdorff product formulas. We show how this technique can be used to realize a number of operations of interest, including polynomials of annihilation and creation operators, namely $\left(a{)}^p\right(a^{†}{)}^q$for integer $p,q$. We show examples of this paradigm including obtaining universal control within a subspace of the entire Fock space of an oscillator, state preparation of a fixed photon number in the cavity, simulation of the Jaynes–Cummings Hamiltonian, and simulation of the Hong-Ou-Mandel effect. This work demonstrates how techniques from Hamiltonian simulation can be applied to better control hybrid qubit-boson devices. 

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5. Quantization of spherically symmetric loop quantum gravity coupled to a scalar field and a clock: the asymptotic limit

   https://doi.org/10.1088/1361-6382/ad0b9d  

   Gambini, Rodolfo; Pullin, Jorge (November 2023, Classical and Quantum Gravity)

   Abstract We continue our work on the study of spherically symmetric loop quantum gravity coupled to two spherically symmetric scalar fields, one which acts as a clock. As a consequence of the presence of the latter, we can define a true Hamiltonian for the theory. The spherically symmetric context allows to carry out precise detailed calculations. Here we study the theory for regions of large values of the radial coordinate. This allows us to define in detail the vacuum of the theory and study its quantum states, yielding a quantum field theory on a quantum space time that makes contact with the usual treatment on classical space times. 

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