Quantum Physics Demystified
The first popular science book about Many-Interacting Worlds and MIWOI.
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|Book Sample 2 - Dark Coherence Experiment|
|MIWOI||The Dark Coherence Experiment was formulated during 2019. The version below was received for publication March 13, 2020, with the most recent revision published here April 3, 2020.|
|Dark Matter and Energy||
Dark matter is a posited form of matter that interacts only weakly with other matter yet expresses a gravitational field that accounts for large scale structures such as galaxies. Without dark matter, many galaxies would fly apart since they have too little visible matter to be held together by gravity. Some calculations indicate the matter holding galaxies together is 85% dark matter, that is, 85% unaccounted for. As of this writing (2020) there is no consensus among physicists regarding exactly what dark matter actually is.
Dark energy is the name given to a force or effect that is accelerating the expansion of the observable universe. Cosmologists currently estimate the amount of dark energy to be roughly twice as much as all other energy and matter combined, including dark matter. Though it is thought to be spread very thinly across space, when summed across the vastness of known space, dark energy becomes the most dominant, common form of energy/mass.
If an object cohered in superposition has a stronger gravitational field than an equivalent decohered object, maybe that difference can be measured. For small objects we can manipulate in a lab, the magnitude of the difference is likely miniscule. Whether current technology can measure such a tiny difference is uncertain. A new device might be needed, such as what I call a coherometer, as described next.
If we are to directly measure gravitational effects of objects from other worlds interacting within our world, extreme precision is necessary because such interaction is expected to be very small in any localized area. As experienced by those building quantum computers, quantum coherence is very delicate. The tiniest leak of information can trigger decoherence. Coherence's extreme fragility can be leveraged to make very sensitive measurements. I propose an invention I call a coherometer.
A coherometer is any device that renders a useful measurement by detecting the presence or absence of quantum coherence. A coherometer can make precise measurements by exploiting the fragility of coherence.
One possible coherometer design modifies a Mach-Zehnder interferometer so that during operation the apparatus exhibits observable information that reveals which-way information to the environment and thus triggers decoherence. For example, a Mach-Zehnder interferometer coupled with a gravitational field strength measuring device creates a coherometer that can explore the mass of cohered versus decohered particles. Such a gravimetric coherometer is the type needed for this chapter's dark matter/energy experiment.
Due to gravity's relative weakness, it is difficult to measure. The challenge of the Dark Coherence experiment is measuring a tiny amount of mass to see if its gravitational field varies based on its coherence. More specifically, rather than accurately measure that field, the experiment needs to compare the fields of cohered versus decohered matter.
While in theory a torsion balance apparatus of the style Henry Cavendish used to measure gravity during the late 18th century would work, its sensitivity is almost certainly insufficient to probe dark matter. A version of it greatly enhanced with 21st century technology might be sufficient. Even higher sensitivity is likely needed though, perhaps something similar to that described by Osborne et al. in "Trapped atoms to probe gravity" (November 8, 2019 Science) in which the authors outline precise calculations of gravity via interferometric measurement of the superposition state of trapped atoms.
Though probably impractical to implement, there is a certain elegance to a Cavendish-style device because even if we do not directly measure a difference in gravitational field, any difference exposed to the environment around us will trigger decoherence. For his purpose, Cavendish needed to isolate his device from vibrations and other outside influences. Such isolation is unnecessary in a coherometer since vibrations, air currents, etc. will not trigger decoherence, only which-way information will.
For the following Dark Coherence experiment, the choice of implementation of the gravitational field measuring device is left to the experimenter.
|The Dark Coherence Experiment||
MIWOI 1) accounts for the double-slit experiment's results by stating interference takes place between cohered particles in different worlds, and 2) speculates such coherence is involved with dark matter and/or energy.
The following Dark Coherence (DC) experiment, with an apparatus of sufficiently sensitive construction, explores if the gravitational field of particles varies based on their coherence. Such differences might help explain dark matter and/or dark energy. I request that anyone inspired to undertake a DC experiment please notify me so we can stay in contact.
MIWOI suggests particles cohered in superposition may have a stronger gravitational field than decohered particles. The primary challenge of measuring a cohered particle is that measurement causes it to decohere. Various measuring techniques will be employed, including interaction-free measurement.
The DC experiment's setup starts with the coherometer described in the prior topic. The experiment employs gravimetry to reveal which-way information that in turn triggers decoherence.
Something helpful for calibration, as well as certain phases of the experiment, is a definitive way to gather which-way information so, at will, the experiment's particles can be forced to decohere. To the coherometer add which-way monitors, via any of the common methods. As seen in other experiments, when which-way information is knowable, particles sent through the apparatus are not cohered in superposition, and thus no interference (no wave behavior) occurs in the interferometer. Conversely, when which-way information is not knowable, particles remain cohered in superposition, and wave behavior occurs.
The choice of gravimetric device is left to the experimenter. The device needs to be of adjustable sensitivity, and to render an observable change in response to gravitational fields of different strength. To facilitate field measurement, employ particles of the largest mass practical in the coherometer. As with all experiments involving quantum decoherence, the operation of the apparatus and/or its results need to be observed (at least by the environment) in order for decoherence to be realized.
The experiment tests if the gravitational field of a particular quantity of cohered particles g(c) associated with cohered many-worlds differs from that of the same quantity of their decohered counterparts g(d) of separated, decohered worlds. By adjusting the sensitivity of the gravimetric measurements while the coherometer is operating, certain phases of the experiment explore the zone of transition between cohered and decohered particles, looking for revealing discontinuities.
During operation of a Mach-Zehnder interferometer, when particle which-way information is known, each decohered particle follows one particular path. When which-way information is not known, at present it remains uncertain which path a given particle follows. MIWOI posits that during the latter situation a "cloud" consisting of cohered particles of different worlds transits the interferometer at the same time, with separate portions of the cloud taking the two different possible paths.
If such splitting of the cloud of cohered particles occurs, the maximum instantaneous gravitational field found along one of the two paths will be g(c)/2. Since a decohered particle is believed to not follow both paths, its maximum instantaneous field along one of the paths will be g(d), and the average of the two paths g(d)/2. Whether "instantaneous" measurement is possible depends on the technology available, and the gravimetric device chosen. The experimenter will need to consider the responsiveness of the device: an instantaneous measurement can capture the maximum field strength of a single particle, whereas a slower response that measures a stream of particles yields an average field strength.
The DC experiment offers multiple ways to compare g(c) with g(d), expressed as five phases, each of which independently compares g(c) and g(d). Various other comparison tests can also be done with this apparatus. The measured values of g(c) and g(d) are useful only as compared to each other during a given phase. Note also the particular values obtained for g(c) and g(d) will vary based on the equipment employed.
Phase 1 - Apparatus calibration and demonstration of concept
Phase 1 comments: Though measurement of the particle's gravitational field is an indirect way to learn which-way information, that measurement, if possible on such a small mass, is expected to trigger decoherence. This phase verifies the equipment is functioning as expected. If the field of individual particles is too small to measure, use a large stream of particles, or multiple streams. as in Phase 2.
Phase 2 - Employ streams of a large number of particles
Phase 2 comments: The expected effect of a stream of a large number of particles is to average the gravitational field. Consequently, if g(c) = g(d), cohered particles that split in half and take both paths simultaneously will in step 2.7 result in the same average field as indivisible decohered particles, half the number of which take the path measured in step 2.3. However, if the values obtained in steps 2.3 and 2.7 differ, it indicates coherence has an effect on the gravitational field expressed. An open question is whether reality will consider such measurement of a large stream of particles to be indirect which-way measurement of each particle. If such measurements do trigger decoherence, an interaction-free measurement will be needed, as in Phase 3.
Phase 3 - Explore decoherence zone
Phase 3 comments: This phase uses the coherometer's unique abilities. In Wheeler's delayed choice experiment, modification of the apparatus while the particle is "in flight" yields results as if the apparatus change had been in effect all along. If that were to hold true in step 3.4 above, the gravimetric device would be unable to detect g(d), thus which-way information would be lacking, and wave behavior would result, the usual combination. In this experiment, the particle is changing upon decoherence. In other experiments, wave behavior has never been observed after decoherence, so that is expected to also be the case in step 3.4. If, despite careful sensitivity reduction, wave behavior nevertheless occurs in step 3.4 here, it indicates the apparatus has actually skipped ahead to step 3.5, suggesting g(c) = g(d).
Phase 4 - Check for splitting of mass between paths
Phase 4 comments: When an interferometer of this type displays wave behavior, it might be that 50% of the cohered mass follows one path, and 50% follows the other. After decoherence, 50% of the particles follow one path, 50% the other. High-speed gravitational field measurement of the former should peak at 50%, while that of the latter at 100%. Due to such a division, depending on the response speed of the measuring device, peak gravitational field measurement of one path during coherence might show a smaller value than when decohered particle behavior is observed, even if the presumed cloud of cohered particles has a stronger total field than their single-particle decohered version. This would also be the case if g(c) = g(d). Consequently, such a finding does not prove g(c) > g(d), but it does indicate that during wave behavior and interference, something with a gravitational field is taking both paths concurrently.
Phase 5 - Direct measurement
Phase 5 comments: A drawback to the phase 5 approach is that it does not measure particles while they are separated along different paths, which is the most revealing time/place. Ideally, if we know a particle is following path A, we would like to directly measure the gravitational field along path B to see if it is non-zero; however, decoherence makes that impossible.
|Dark Coherence Experiment Results||
With a sufficiently sensitive apparatus that skirts decoherence complications, both a negative (g(c) = g(d)) and positive (g(c) > g(d)) result of this experiment will be enlightening. A positive result, one that shows cohered particles with a different gravitational field, is the more interesting since it suggests new physics to study.
A negative result, that is, a finding of g(c) = g(d), in the phases above should not too quickly be considered conclusive. Yet to be explored are ways to make weak measurements, ones that might not trigger decoherence. For example, dampening the gravimetric instrument's response to the field in phases 1 and 2 above might mask which-way information of individual particles, and thus avoid the decoherence problem. As dampener, the inertia of a Cavendish-style torsion balance would do, but also make the device insensitive to small fields.
For MIWOI, when such an experiment is performed, it is concurrently being performed in nearby worlds. A double-slit interference pattern builds even with individually-sent particles because those particles interfere with their neighbors in nearby worlds. A positive result from the DC experiment demonstrates the gravitational field of particles in other worlds influences our world. Such ethereal mass "hidden" in other worlds, but that gravitationally influences our world, seems a dark matter candidate.
A positive result's apparent excess mass might equal the sum of the contributions of many worlds, with some (the closer?) worlds contributing more. Perhaps a single formula can be devised to account for this mass, one that will also match the apparent effects of dark matter.
A positive result would also establish a link between quantum superposition and gravity that can be probed via further experiments. Conversely, a negative result on an apparatus of sufficient sensitivity would rule out such links.