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Information scrambling refers to the rapid spreading of initially localized information over an entire system, via the generation of global entanglement. This effect is usually detected by measuring a temporal decay of the out-of-time order correlators. However, in experiments, decays of these correlators suffer from fake positive signals from various sources, e.g., decoherence due to inevitable couplings to the environment, or errors that cause mismatches between the purported forward and backward evolutions. In this work, we provide a simple and robust approach to single out the effect of genuine scrambling. This allows us to benchmark the scrambling process by quantifying the degree of the scrambling from the noisy backgrounds., Comment: v2: published version; added new simulations on IBM quantum computers

The bottom quark forward-backward asymmetry (AFBb) data at LEP exhibits a long-standing discrepancy with the standard model prediction. We propose a novel method to probe the Zbb¯ interactions through gg→Zh production at the LHC, which is sensitive to the axial-vector component of the Zbb¯ couplings. The apparent degeneracy of the anomalous Zbb¯ couplings implied by the LEP precision electroweak measurements seems to be resolved by the current 13 TeV LHC Zh data, which is, however, dominated by the two data points with high transverse momentum of Z boson whose central values are in conflict with the standard model prediction. We also show the potential of the HL-LHC to either verify or exclude the anomalous Zbb¯ couplings observed at LEP through measuring the Zh production rate at the HL-LHC, and this conclusion is not sensitive to the possible new physics contribution induced by top quark or Higgs boson anomalous couplings in the loop.

The bottom quark forward-backward asymmetry (A_{FB}^{b}) data at LEP exhibits a long-standing discrepancy with the standard model prediction. We propose a novel method to probe the Zbb[over ¯] interactions through gg→Zh production at the LHC, which is sensitive to the axial-vector component of the Zbb[over ¯] couplings. The apparent degeneracy of the anomalous Zbb[over ¯] couplings implied by the LEP precision electroweak measurements seems to be resolved by the current 13 TeV LHC Zh data, which is, however, dominated by the two data points with high transverse momentum of Z boson whose central values are in conflict with the standard model prediction. We also show the potential of the HL-LHC to either verify or exclude the anomalous Zbb[over ¯] couplings observed at LEP through measuring the Zh production rate at the HL-LHC, and this conclusion is not sensitive to the possible new physics contribution induced by top quark or Higgs boson anomalous couplings in the loop.

We explore nonadiabatic quantum phase transitions in an Ising spin chain with a linearly time-dependent transverse field and two different spins per unit cell. Such a spin system passes through critical points with gapless excitations, which support nonadiabatic transitions. Nevertheless, we find that the excitations on one of the chain sub-lattices are suppressed in the nearly-adiabatic regime exponentially. Thus, we reveal a coherent mechanism to induce exponentially large density separation for different quasiparticles., Comment: v2: published version. 5+5 pages, 3+1 figures

A time-reversed dynamics unwinds information scrambling, which is induced during the time-forward evolution with a complex Hamiltonian. We show that if the scrambled information is, in addition, partially damaged by a local measurement, then such a damage can still be treated by application of the time-reversed protocol. This information recovery is described by the long-time saturation value of a certain out-of-time-ordered correlator of local variables. We also propose a simple test that distinguishes between quantum and reversible classical chaotic information scrambling., Comment: 5+2 pages, 3+3 figures; V3: Published version; V2: Improved presentation, new model study added

We demonstrate analytically and verify numerically that the out-of-time order correlator is given by the thermal average of Loschmidt echo signals. This provides a direct link between the out-of-time-order correlator -- a recently suggested measure of information scrambling in quantum chaotic systems -- and the Loschmidt echo, a well-appreciated familiar diagnostic that captures the dynamical aspect of chaotic behavior in the time domain, and is accessible to experimental studies., V4: final version for publication; improved presentation; 6+8 pages, 5 figures. V3: a major improvement of an already good paper

It is a fundamental problem in physics of what principle limits the correlations as predicted by our current description of nature, based on quantum mechanics. One possible explanation is the "global exclusivity" principle recently discussed in Phys. Rev. Lett. 110, 060402 (2013). In this work we show that this principle actually has a much stronger restriction on the probability distribution. We provide a tight constraint inequality imposed by this principle and prove that this principle singles out quantum correlations in scenarios represented by any graph. Our result implies that the exclusivity principle might be one of the fundamental principles of nature., Comment: 5 pages, 1 figure