Turbulence in stratified and rotating turbulent flows is characterized by an interplay between waves and eddies, resulting in continuous exchanges between potential and kinetic energy. Here, we study how these processes affect the turbulent energy cascade from large to small scales, which manifests itself by an irreversible evolution of the relative kinetic energy between two tracer particles. We find that when $r_0$, the separation between particles, is below a characteristic length ${\ell }_t$, potential energy is on average transferred to kinetic energy, reducing time irreversibility, and conversely when $r_0>{\ell }_t$. Our Letter reveals that the scale ${\ell }_t$ coincides with the buoyancy length scale $L_B$ over a broad range of configurations until a transition to a wave-dominated regime is reached.

Counterflow superfluidity in a system with $N\ge 3$ components is distinctively different from the $N=2$ case. The key feature is the difference between the number ($N$) of elementary vortex excitations and the number ($N-1$) of independent branches of phonon modes, that is, the number of superfluid modes is larger than the number of ordered phase variables. We formulate a hydrodynamic theory of this state. We show how all the dynamical and statistical aspects of this (“Borromean”) type of ordering are naturally described by effective $N$-component theory featuring compact-gauge invariance. We also discuss how off diagonal intercomponent couplings convert the Borromean supercounterfluid into a Borromean insulator, with an emphasis on the properties of a nontrivial state with broken time-reversal symmetry.

Strain-controlled criticality governs the elasticity of jamming and fiber networks. While the upper critical dimension of jamming is believed to be $d_u=2$, non-mean-field exponents are observed in numerical studies of 2D and 3D fiber networks. The origins of this remains unclear. In this study we propose a minimal mean-field model for strain-controlled criticality of fiber networks. We then extend this to a phenomenological field theory, in which non-mean-field behavior emerges as a result of the disorder in the network structure. We predict that the upper critical dimension for such systems is $d_u=4$ using a Gaussian approximation. Moreover, we identify an order parameter for the phase transition, which has been lacking for fiber networks to date.

A fundamental question about biomolecular condensates is how distinct condensates can emerge from the interplay of different components. Here we present a minimal model of droplet differentiation where phase separated droplets demix into two types with different chemical modifications triggered by enzymatic reactions. We use numerical solutions to Cahn-Hilliard equations with chemical reactions and an effective droplet model to reveal the switchlike behavior. Our work shows how condensate identities in cells could result from competing enzymatic actions.

A central challenge in the verification of quantum computers is benchmarking their performance as a whole and demonstrating their computational capabilities. In this Letter, we find a universal model of quantum computation, Bell sampling, that can be used for both of those tasks and thus provides an ideal stepping stone toward fault tolerance. In Bell sampling, we measure two copies of a state prepared by a quantum circuit in the transversal Bell basis. We show that the Bell samples are classically intractable to produce and at the same time constitute what we call a “circuit shadow”: from the Bell samples we can efficiently extract information about the quantum circuit preparing the state, as well as diagnose circuit errors. In addition to known properties that can be efficiently extracted from Bell samples, we give several new and efficient protocols: an estimator of state fidelity, an error-mitigated estimator of Pauli expectation values, a test for the depth of a circuit, and an algorithm to estimate a lower bound on the number of $T$ gates in the circuit. With some additional measurements, the latter algorithm can be used to learn a full description of states prepared by circuits with low $T$ count.

Primordial black holes (PBHs) and the violation of the null energy condition (NEC) have significant implications for our understanding of the very early Universe. We present a novel approach to generate PBHs via the NEC violation in a single-field inflationary scenario. In our scenario, the Universe transitions from a first slow-roll inflation stage with a Hubble parameter $H=H_{\inf 1}$ to a second slow-roll inflation stage with $H=H_{\inf 2}\gg H_{\inf 1}$, passing through an intermediate stage of NEC violation. The NEC violation naturally enhances the primordial scalar power spectrum at a certain wavelength, leading to the production of PBHs with masses and abundances of observational interest. We also investigate the phenomenological signatures of scalar-induced gravitational waves resulting from the enhanced density perturbations. Our work highlights the potential of utilizing a combination of PBHs, scalar-induced gravitational waves, and primordial gravitational waves as a valuable probe for studying NEC violation during inflation, opening up new avenues for exploring the early Universe.

We propose a novel method to significantly enhance the signal rate in qubit-based dark matter detection experiments with the help of quantum interference. Various quantum sensors possess ideal properties for detecting wavelike dark matter, and qubits, commonly employed in quantum computers, are excellent candidates for dark matter detectors. We demonstrate that, by designing an appropriate quantum circuit to manipulate the qubits, the signal rate scales proportionally to $n_{\mathrm{q}}^2$, with $n_{\mathrm{q}}$ being the number of sensor qubits, rather than linearly with $n_{\mathrm{q}}$. Consequently, in the dark matter detection with a substantial number of sensor qubits, a significant increase in the signal rate can be expected. We provide a specific example of a quantum circuit that achieves this enhancement by coherently combining the phase evolution in each individual qubit due to its interaction with dark matter. We also demonstrate that the circuit is fault tolerant to dephasing noises, a critical quantum noise source in quantum computers. The enhancement mechanism proposed here is applicable to various modalities for quantum computers, provided that the quantum operations relevant to enhancing the dark matter signal can be applied to these devices.

Sequential ionization of fullerene cluster ions $({\mathrm{C}}_{60}{)}_n^{+}$ within multiply charged helium nanodroplets leads to the intriguing phenomenon of forming and stabilizing doubly and triply charged fullerene oligomers. While the formation of doubly charged dimers $({\mathrm{C}}_{60}{)}_2^{2+}$ has been predicted in earlier studies, the observation of even triply charged ones $({\mathrm{C}}_{60}{)}_2^{3+}$ is highly surprising. This remarkable resilience against Coulomb explosion is achieved through efficient cooling within the superfluid environment of helium nanodroplets and a sequential ionization scheme that populates covalently bound or physisorbed fullerene dimers. Calculations support the stability of four differently bonded $({\mathrm{C}}_{60}{)}_2^{2+}$ and $({\mathrm{C}}_{60}{)}_2^{3+}$ isomers and predict a low Coulomb barrier ($<0.4\mathrm{eV}$) preventing even dissociation of cold van der Waals complexes.

Hong-Ou-Mandel interference is an intrinsic quantum phenomenon that goes beyond the possibilities of classical physics, and enables numerous applications in quantum information science. While the photon-photon interaction is fundamentally limited to the bosonic nature of photons and the restricted phase responses from commonly used unitary optical elements, we present that a nonunitary material provides an alternative degree of freedom to control the two-photon quantum interference, even revealing anomalous quantum interference paths that do not exist in a unitary configuration. An elaborate lossy multilayer graphene that can work as a nonunitary beam splitter is used to explore its tunability over the effective photon-photon interaction in spatial modes, and to verify the particle exchange statistics by its experimental implementation in quantum state filter. This scheme is further extended to observe four-dimensional quantum interference patterns on the lossless and lossy beam splitters, and thus show its applicability even in higher-dimensional Hilbert space.

The leaf vein network is a hierarchical vascular system that transports water and nutrients to the leaf cells. The thick primary veins form a branched network, while the secondary veins can develop closed loops forming a well-defined cellular structure. Through extensive analysis of a variety of distinct leaf species, we discover that the apparently disordered cellular structures of the secondary vein networks exhibit a universal hyperuniform organization and possess a hidden order on large scales. Disorder hyperuniform systems lack conventional long-range order, yet they completely suppress normalized infinite-wavelength density fluctuations like crystals. Specifically, we find that the distributions of the geometric centers associated with the vein network loops possess a vanishing static structure factor in the limit that the wave number $k$ goes to 0, i.e., $S(k)\sim k^{\alpha }$, where $\alpha \approx 0.64\pm 0.021$, providing an example of class III hyperuniformity in biology. This hyperuniform organization leads to superior efficiency of diffusive transport, as evidenced by the much faster convergence of the time-dependent spreadability $\mathcal{S}(t)$ to its longtime asymptotic limit, compared to that of other uncorrelated or correlated disordered but nonhyperuniform organizations. Our results also have implications for the discovery and design of novel disordered network materials with optimal transport properties.

We develop the mathematics needed to treat the interaction of geometry and stress at any isotropic spacetime singularity. This enables us to handle the Einstein equations at the initial singularity and characterize allowed general relativistic stress-energy tensors. Their leading behaviors are dictated by an initial hypersurface conformal embedding. We also show that an isotropic big bang determines a canonical nonsingular metric on and about the initial hypersurface as well as a cosmological time. This assigns a volume and energy to the initial point singularity.

The first search for singly produced narrow resonances decaying to three well-separated hadronic jets is presented. The search uses proton-proton collision data corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ at $\sqrt{s}=13\mathrm{TeV}$, collected at the CERN LHC. No significant deviations from the background predictions are observed between 1.75 and 9.00 TeV. The results provide the first mass limits on a right-handed boson $Z_R$ decaying to three gluons and on an excited quark decaying via a vector boson to three quarks, as well as updated limits on a Kaluza-Klein gluon decaying via a radion to three gluons.

To search for low-energy resonant structures in isospin $T=3/2$ three-body systems, we have performed the experiments ${}^3\mathrm{H}(t,{}^3\mathrm{He})3n$ and ${}^3\mathrm{He}({}^3\mathrm{He},t)3p$ at intermediate energies. For the $3n$ experiment, we have newly developed a thick Ti-${}^3\mathrm{H}$ target that has the largest tritium thickness among targets of this type ever made. The $3n$ experiment for the first time covered the momentum-transfer region as low as $15\mathrm{MeV}/c$, which provides ideal conditions for producing fragile systems. However, in the excitation-energy spectra we obtained, we did not observe any distinct peak structures. This is in sharp contrast to tetraneutron spectra. The distributions of the $3n$ and $3p$ spectra are found to be similar, except for the displacement in energy due to Coulomb repulsion. Comparisons with theoretical calculations suggest that three-body correlations exist in the $3n$ and $3p$ systems, although not enough to produce a resonant peak.

It is well known that the set of statistics that can be observed in a Bell-type experiment is limited by quantum theory. Unfortunately, tools are missing to identify the precise boundary of this set. Here, we propose to study the set of quantum statistics from a dual perspective. By considering all Bell expressions saturated by a given realization, we show that the Clauser-Horne-Shimony-Holt expression can be decomposed in terms of extremal Tsirelson inequalities that we identify. This brings novel insight into the geometry of the quantum set in the (2,2,2) scenario. Furthermore, this allows us to identify all the Bell expressions that are able to self-test the Tsirelson realization.