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1. Spectrum of quantum KdV hierarchy in the semiclassical limit

   https://doi.org/10.1007/JHEP09(2022)169  

   Dymarsky, Anatoly; Kakkar, Ashish; Pavlenko, Kirill; Sugishita, Sotaro (September 2022, Journal of High Energy Physics)

   A<sc>bstract</sc> We employ semiclassical quantization to calculate spectrum of quantum KdV charges in the limit of large central chargec. Classically, KdV chargesQ_2n−1generate completely integrable dynamics on the co-adjoint orbit of the Virasoro algebra. They can be expressed in terms of action variablesI_k, e.g. as a power series expansion. Quantum-mechanically this series becomes the expansion in 1/c, while action variables become integer-valued quantum numbersn_i. Crucially, classical expression, which is homogeneous inI_k, acquires quantum corrections that include terms of subleading powers inn_k. At first two non-trivial orders in 1/cexpansion these “quantum” terms can be fixed from the analytic form ofQ_2n−1acting on the primary states. In this way we find explicit expression for the spectrum ofQ_2n−1up to first three orders in 1/cexpansion. We apply this result to study thermal expectation values ofQ_2n−1and free energy of the KdV Generalized Gibbs Ensemble. 

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2. Super-resolved time–frequency measurements of coupled phonon dynamics in a 2D quantum material

   https://doi.org/10.1038/s41598-022-22055-w  

   Gentry, Christian; Liao, Chen-Ting; You, Wenjing; Ryan, Sinéad A.; Varner, Baldwin Akin; Shi, Xun; Guan, Meng-Xue; Gray, Thomas; Temple, Doyle; Meng, Sheng; et al (November 2022, Scientific Reports)

   Abstract Methods to probe and understand the dynamic response of materials following impulsive excitation are important for many fields, from materials and energy sciences to chemical and neuroscience. To design more efficient nano, energy, and quantum devices, new methods are needed to uncover the dominant excitations and reaction pathways. In this work, we implement a newly-developed superlet transform—a super-resolution time-frequency analytical method—to analyze and extract phonon dynamics in a laser-excited two-dimensional (2D) quantum material. This quasi-2D system, 1T-TaSe₂, supports both equilibrium and metastable light-induced charge density wave (CDW) phases mediated by strongly coupled phonons. We compare the effectiveness of the superlet transform to standard time-frequency techniques. We find that the superlet transform is superior in both time and frequency resolution, and use it to observe and validate novel physics. In particular, we show fluence-dependent changes in the coupled dynamics of three phonon modes that are similar in frequency, including the CDW amplitude mode, that clearly demonstrate a change in the dominant charge-phonon couplings. More interestingly, the frequencies of the three phonon modes, including the strongly-coupled CDW amplitude mode, remain time- and fluence-independent, which is unusual compared to previously investigated materials. Our study opens a new avenue for capturing the coherent evolution and couplings of strongly-coupled materials and quantum systems. 

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3. Time-varying quantum channel models for superconducting qubits

   https://doi.org/10.1038/s41534-021-00448-5  

   Etxezarreta Martinez, Josu; Fuentes, Patricio; Crespo, Pedro; Garcia-Frias, Javier (July 2021, npj Quantum Information)

   Abstract The decoherence effects experienced by the qubits of a quantum processor are generally characterized using the amplitude damping time (T₁) and the dephasing time (T₂). Quantum channel models that exist at the time of writing assume that these parameters are fixed and invariant. However, recent experimental studies have shown that they exhibit a time-varying (TV) behaviour. These time-dependant fluctuations ofT₁andT₂, which become even more pronounced in the case of superconducting qubits, imply that conventional static quantum channel models do not capture the noise dynamics experienced by realistic qubits with sufficient precision. In this article, we study how the fluctuations ofT₁andT₂can be included in quantum channel models. We propose the idea of time-varying quantum channel (TVQC) models, and we show how they provide a more realistic portrayal of decoherence effects than static models in some instances. We also discuss the divergence that exists between TVQCs and their static counterparts by means of a metric known as the diamond norm. In many circumstances this divergence can be significant, which indicates that the time-dependent nature of decoherence must be considered, in order to construct models that capture the real nature of quantum devices. 

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4. Broken conformal window

   https://doi.org/10.1007/JHEP04(2025)152  

   Kondo, Dan; Murayama, Hitoshi; Noether, Bea; Varier, Digvijay Roy (April 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> We show that near the edges of the conformal window of supersymmetric SU(N_c) QCD, perturbed by Anomaly Mediated Supersymmetry Breaking (AMSB), chiral symmetry can be broken depending on the initial conditions of the RG flow. We do so by perturbatively expanding around Banks-Zaks fixed points and taking advantage of Seiberg duality. Interpolating between the edges of the conformal window, we predict that non-supersymmetric QCD breaks chiral symmetry up toN_f≤ 3N_c− 1, while we cannot say anything definitive forN_f≥ 3N_cat this moment. 

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5. Engineered chirality of one-dimensional nanowires

   https://doi.org/10.1126/sciadv.adx4761  

   Briggeman, Megan; Mansfield, Elliott; Kombe, Johannes; Damanet, François; Lee, Hyungwoo; Tang, Yuhe; Yu, Muqing; Biswas, Sayanwita; Li, Jianan; Huang, Mengchen; et al (June 2025, Science Advances)

   The origin and function of chirality in DNA, proteins, and other building blocks of life represent a central question in biology. Observations of spin polarization and magnetization associated with electron transport through chiral molecules, known collectively as the chiral induced spin selectivity effect, suggest that chirality improves electron transfer. Using reconfigurable nanoscale control over conductivity at the LaAlO₃/SrTiO₃interface, we create chiral electron potentials that explicitly lack mirror symmetry. Quantum transport measurements on these chiral nanowires reveal enhanced electron pairing persisting to high magnetic fields (up to 18 tesla) and oscillatory transmission resonances as functions of both magnetic field and chemical potential. We interpret these resonances as arising from an engineered axial spin-orbit interaction within the chiral region. The ability to create one-dimensional electron waveguides with this specificity creates opportunities to test, via analog quantum simulation, theories about chirality and spin-polarized electron transport in one-dimensional geometries. 

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