What is fine-tuning in physics?
What is fine-tuning in physics?
In theoretical physics, fine-tuning is the process in which parameters of a model must be adjusted very precisely in order to fit with certain observations.
Is fine-tuning possible?
It’s as if there are a large number of dials that have to be tuned to within extremely narrow limits for life to be possible in our universe. It is extremely unlikely that this should happen by chance, but much more likely that this should happen, if there is such a person as God.
What is an example of fine-tuning?
Technological devices are paradigmatic examples of fine-tuning. Whether they function as intended depends sensitively on parameters that describe the shape, arrangement, and material properties of their constituents, e.g., the constituents’ conductivity, elasticity and thermal expansion coefficient.
How do you do fine-tuning?
1, fine-tuning consists of the following four steps: Pretrain a neural network model, i.e., the source model, on a source dataset (e.g., the ImageNet dataset). Create a new neural network model, i.e., the target model. This copies all model designs and their parameters on the source model except the output layer.
Is the Universe finely tuned?
The fact that our Universe has such a perfect balance between the expansion rate and the energy density — today, yesterday, and billions of years ago — is a clue that our Universe really is finely tuned.
What is the learning rate for fine-tuning?
The learning rate in fine-tune CNN layers is set to 0.0001, while the learning rate in fine-tune BN layers is set into 0.01. We found that such a learning rate setting can make the network obtain better results.
What does it mean to be fine tuned?
Definition of fine-tuned 1 : precisely adjusted for the highest level of performance, efficiency, or effectiveness a fine-tuned machine His voice on “Always Late with Your Kisses” rolled along its cordillera of syllables like a fine-tuned sports car.—
How many fine-tuning constants are there?
Codata lists about 360 different fine-tune constants, which have to be just right in order to have a life-permitting universe. The parameters of the standard model of particle physics are “unnaturally” small (in various technical senses), which has driven much of the search for physics beyond the standard model.
Why is the universe unbalanced?
A decade ago cosmologists began to suspect that the universe might be bizarrely lopsided. Hints of a universal imbalance emerged from the afterglow of the big bang, known as the cosmic microwave background, or CMB, which is dotted with hot and cold spots signifying fluctuations in the density of matter.
What is the difference between transfer learning and fine-tuning?
Transfer learning is when a model developed for one task is reused to work on a second task. Fine-tuning is one approach to transfer learning where you change the model output to fit the new task and train only the output model. In Transfer Learning or Domain Adaptation, we train the model with a dataset.
What happens when learning rate is too high?
A learning rate that is too large can cause the model to converge too quickly to a suboptimal solution, whereas a learning rate that is too small can cause the process to get stuck.
Is gravity fine-tuned?
Gravity, like the scale of the universe, is also finely tuned. This force is represented by the gravitational constant, G. If G had been weaker, it would not have had the strength to overcome the initial explosive forces of the Big Bang and bring particles in the universe together, forming stars and planets.
Why antimatter is very rare today?
But today, there’s nearly no antimatter left in the universe – it appears only in some radioactive decays and in a small fraction of cosmic rays. So what happened to it? Using the LHCb experiment at CERN to study the difference between matter and antimatter, we have discovered a new way that this difference can appear.
What happens if you touch antimatter?
Our bodies also contain potassium-40, which means positrons are being emitted from you, too. Antimatter annihilates immediately on contact with matter, so these antimatter particles are very short-lived.
This is known as fine-tuning, and it really is a problem in physics. explain why the value of such a finely-tuned parameter like the cosmological constant (or the value of dark energy) has the value that it does.
How do you measure fine-tuning?
Although fine-tuning was traditionally measured by ad hoc fine-tuning measures, such as the Barbieri-Giudice-Ellis measure, over the past decade many scientists recognized that fine-tuning arguments were a specific application of Bayesian statistics. ^ Leslie, John (1998). Modern Cosmology & Philosophy.
What is a finely-tuned situation?
a finely-tuned state, or a state of unstable equilibrium. A much more stable position is for the ball to be down somewhere at the bottom of the valley. Whenever we encounter a finely-tuned physical situation, there are good reasons to seek a physically-motivated explanation for it.
What are some examples of finely-tuned things in the universe?
In the Universe, there are many things that are finely-tuned. The expanding Universe itself is a fantastic example. At the earliest moment of the hot Big Bang, the fabric of space itself was expanding at a particular rate (the Hubble expansion rate) that happened to be enormous.