Superdeterministic hidden-variables models II: conspiracy

We prove that superdeterministic models of quantum mechanics are conspiratorial in a mathematically well-defined sense, by further development of the ideas presented in a previous article A . We consider a Bell scenario where, in each run and at each wing, the experimenter chooses one of N devices to determine the local measurement setting. We prove, without assuming any features of quantum statistics, that superdeterministic models of this scenario must have a finely tuned distribution of hidden variables. Specifically, fine-tuning is required so that the measurement statistics depend on the measurement settings but not on the details of how the settings are chosen. We quantify this as the overhead fine-tuning F of the model, and show that F > 0 (corresponding to ‘fine-tuned’) for any N > 1. The notion of fine-tuning assumes that arbitrary (‘non-equilibrium’) hidden-variables distributions are possible in principle. We also show how to quantify superdeterministic conspiracy without using non-equilibrium. This second approach is based on the fact that superdeterministic correlations can mimic actual signalling. We argue that an analogous situation occurs in equilibrium where, for every run, the devices that the hidden variables are correlated with are coincidentally the same as the devices in fact used. This results in extremely large superdeterministic correlations, which we quantify as a drop of an appropriately defined formal entropy. Non-local and retrocausal models turn out to be non-conspiratorial according to both approaches.

Entangled baryons: violation of inequalities based on local realism assuming dependence of decays on hidden variables

Bell inequalities are consequences of local realism while violated by quantum mechanics. In particle physics, entangled high energy particles can be produced from a common source, and the decay of each particle plays the role of measurement. However, in a hidden variable theory, the decay could be determined by hidden variables. This loophole killed such approaches to Bell test in particle physics. It is a special form of measurement-setting or free-will loophole, which also exists in other systems. Using entangled baryons, we present new inequalities of local realism with the explicit assumption of the dependence of the decays on hidden variables, as well as the consideration of the statistical mixture of polarizations and the separation of local hidden variables for objects with spacelike distances. These violations closes the measurement-setting loophole once and for all. We propose to use the processes $$\eta _c\rightarrow \varLambda {\bar{\varLambda }}$$ηc→ΛΛ¯ and $$\chi _{c0} \rightarrow \varLambda {\bar{\varLambda }}$$χc0→ΛΛ¯ to test our inequalities, and show that their violations are likely to be observed with the data already collected in BESIII.

Study Measuring Characteristic of the High Intensity Reverberation Acoustic Chamber Performance

Reverberation Acoustic Test Facility (RATF) is a one of the mechanical satellite testing facility in the Assembly, Integration and Test Centre at National Space Agency (ANGKASA). This is the reverberation type of chamber with external volume at 999.5m3, has the capability to regenerate high intensity acoustic noise ambiance that will be experienced during the launching stage. This paper will describe on reverberation chamber characteristics, the noise generating system and capabilities, and the chamber configuration for high intensity acoustic testing in empty chamber condition. This paper recommends the measurement setting for three variant spectrum levels in generating high-intensity acoustic noise from 130dB to 155dB with center frequencies from range 31.5Hz to 1250Hz.