2019年11月1日 星期五 下午4:01 | | | physics.hist-ph updates on arXiv.org |

Authors: Wolfgang Engelhardt

Einstein’s own demonstration of time dilation taken from his book with L. Infeld (1938) is analyzed. His ingenious circumnavigation of an apparent discrepancy between clock synchronisation and Lorentz transformation is discussed.

2019年11月1日 星期五 下午4:01 | | | quant-ph updates on arXiv.org |

Authors: Shi-Dong Liang, Sorin V. Sabau, Tiberiu Harko

We consider a Finslerian type geometrization of the non-relativistic quantum mechanics in its hydrodynamical (Madelung) formulation, by also taking into account the effects of the presence of the electromagnetic fields on the particle motion. In the Madelung representation the Schr\”{o}dinger equation can be reformulated as the classical continuity and Euler equations of classical fluid mechanics in the presence of a quantum potential, representing the quantum hydrodynamical evolution equations. The equation of particle motion can then be obtained from a Lagrangian similar to its classical counterpart. After the reparametrization of the Lagrangian it turns out that the Finsler metric describing the geometric properties of quantum hydrodynamics is a Kropina metric. We present and discuss in detail the metric and the geodesic equations describing the geometric properties of the quantum motion in the presence of electromagnetic fields. As an application of the obtained formalism we consider the Zermelo navigation problem in a quantum hydrodynamical system, whose solution is given by a Kropina metric. The case of the Finsler geometrization of the quantum hydrodynamical motion of spinless particles in the absence of electromagnetic interactions is considered in detail, and the Zermelo navigation problem for this case is also discussed.

2019年11月1日 星期五 下午4:01 | | | quant-ph updates on arXiv.org |

Authors: Riuji Mochizuki

We show that it is possible to explain the quantum measurement process within the framework of quantum mechanics without any additional postulates. The key concept of the theory is decoherence, which appears as an inherent characteristic of quantum mechanics and results from the uncertainty relation. In contrast to environment-induced decoherence, this decoherence exists prior to a measurement being made. To clarify our idea, we examine three elemental experiments: a Stern-Gerlach-like experiment, the Einstein-Podolsky-Rosen-Bohm (EPR-Bohm) experiment, and the double-slit experiment. By considering the first experiment, we explain how the uncertainty relation between position and momentum introduces decoherence prior to measurement. Consideration of the EPR-Bohm experiment leads us to conclude that the correlation of the EPR pair is not a consequence of what is known as the collapse of the wave function. Our theory of decoherence can also be applied to experiments with continuous eigenvalues, such as the double-slit experiment. Consideration of the double-slit experiment leads us to understand how pure quantum mechanics describes the fact that quanta behave as interfering particles.

2019年11月1日 星期五 下午4:01 | | | quant-ph updates on arXiv.org |

Authors: Mahasweta Pandit, Anindita Bera, Aditi Sen De, Ujjwal Sen

We propose a trade-off between the Lipschitz constants of the position and momentum probability distributions for arbitrary quantum states. We refer to the trade-off as a quantum reciprocity relation. The Lipschitz constant of a function may be considered to quantify the extent of fluctuations of that function, and is, in general, independent of its spread. The spreads of the position and momentum distributions are used to obtain the celebrated Heisenberg quantum uncertainty relations. We find that the product of the Lipschitz constants of position and momentum probability distributions is bounded below by a number that is of the order of the inverse square of the Planck’s constant.

2019年11月1日 星期五 下午4:01 | | | quant-ph updates on arXiv.org |

Authors: Roman Schnabel

The detectors of the international gravitational-wave (GW) observatory network are currently taking data with sensitivities improved via squeezing the photon counting noise of the laser light used. Several GW candidate events, such as black-hole mergers, are already in the pipeline to be analyzed in detail. While the brand-new field of GW astronomy relies on squeezed light for reaching higher sensitivities, the physical understanding of such light, although being well-described by quantum theory, is still under discussion. Here, I present a description of why squeezed light, as now being exploited by GW observatories, constitutes rather remarkable physics. I consider the squeezed photon statistics and show its relation to the famous gedanken experiment formulated by Einstein, Podolsky, and Rosen in 1935. My description illuminates ‘quantum weirdness’ in a clear way and might be the starting point for finding the physics of quantum correlations in general, which scientists have been seeking for decades.

2019年11月1日 星期五 下午4:01 | | | gr-qc updates on arXiv.org |

Authors: Nils A. Nilsson

We discuss implications on very-high-energy (VHE) gamma rays, vacuum Cherenkov radiation, and the H 0 tension due to preferred-frame effects in context of Ho\v{r}ava-Lifshitz gravity. Using bounds on parameters of the theory from gravitational-wave observations we derive lower bounds on the threshold energies for these effects, and from the observation of VHE gamma rays and cosmic-ray protons we find constraints on the Ho\v{r}ava-Lifshitz parameter $\beta$. By using a combination of low-redshift data (Sne1a, elliptical and lenticular galaxies, GRB’s, and quasars) we discuss the $H_0$ tension and its appearance as a preferred-frame effect. Specifically we find that the constraint on $\beta$ from detections of cosmic-ray protons is $\beta \lesssim 10^{-24}$ , which is a tighter bound than from gravitational waves.

2019年11月1日 星期五 下午4:01 | | | gr-qc updates on arXiv.org |

Authors: Herbert W. Hamber, Lu Heng Sunny Yu

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum and the CMB temperature angular power spectrum coefficients to high accuracy is often considered a triumph of inflation. In our previous work, we presented an alternative explanation for the matter power spectrum based on nonperturbative quantum field-theoretical methods applied to Einstein’s gravity, instead of inflation models based on scalar fields. In this work, we review the basic concepts and provide further in-depth investigations. We first update the analysis with more recent data sets and error analysis, and then extend our predictions to the CMB angular spectrum coefficients, which we did not consider previously. Then we investigate further the potential freedoms and uncertainties associated with the fundamental parameters that are part of this picture, and show how recent cosmological data provides significant constraints on these quantities. Overall, we find good general consistency between theory and data, even potentially favoring the gravitationally-motivated picture at the largest scales. We summarize our results by outlining how this picture can be tested in the near future with increasingly accurate astrophysical measurements.

2019年10月31日 星期四 下午6:01 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

2019年10月31日 星期四 下午6:00 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

2019年10月31日 星期四 下午6:00 | | | Marco Túlio Quintino, Costantino Budroni, Erik Woodhead, Adán Cabello, and Daniel Cavalcanti | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Marco Túlio Quintino, Costantino Budroni, Erik Woodhead, Adán Cabello, and Daniel Cavalcanti

In contrast with classical physics, in quantum physics some sets of measurements are incompatible in the sense that they cannot be performed simultaneously. Among other applications, incompatibility allows for contextuality and Bell nonlocality. This makes it of crucial importance to develop tools f…

[Phys. Rev. Lett. 123, 180401] Published Thu Oct 31, 2019

2019年10月31日 星期四 下午5:53 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

2019年10月31日 星期四 下午5:46 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

2019年10月29日 星期二 下午6:00 | | | Matthias Wittemer, Frederick Hakelberg, Philip Kiefer, Jan-Philipp Schröder, Christian Fey, Ralf Schützhold, Ulrich Warring, and Tobias Schaetz | | | PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. |

Author(s): Matthias Wittemer, Frederick Hakelberg, Philip Kiefer, Jan-Philipp Schröder, Christian Fey, Ralf Schützhold, Ulrich Warring, and Tobias Schaetz

Quantum theory predicts intriguing dynamics during drastic changes of external conditions. We switch the trapping field of two ions sufficiently fast to tear apart quantum fluctuations, i.e., create pairs of phonons and, thereby, squeeze the ions’ motional state. This process can be interpreted as a…

[Phys. Rev. Lett. 123, 180502] Published Tue Oct 29, 2019

2019年10月28日 星期一 下午2:34 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |

2019年10月28日 星期一 下午2:33 | | | Philsci-Archive: No conditions. Results ordered -Date Deposited. |