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Is Quantum Mechanics The Same As Quantum Physics

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Is It Possible That Quantum Mechanics Is Wrong

Understanding Quantum Mechanics #8: The Tunnel Effect

What is one possible response when we learn in quantum mechanics that a particle can be in more than one place at the same time? Or that particles which are across the galaxy from each other can coordinate their behavior instantaneously? The thought might pop up that possibly quantum mechanics is wrong. The question as to whether quantum mechanics might be wrong can more easily be addressed by breaking it in two:

How Does Quantum Physics Affect Me

You may have heard that an atom consists of a nucleus and electrons that rapidly surround the nucleus. In classical physics it is well known that accelerated charged particles radiate energy. Well, the electrons that move in circles feel acceleration and thus should radiate energy. But if they would lose energy, they should classically come closer and closer to the nucleus, until they collide with it. In other words, classical theory predicts that atoms are unstable. This means you would not exist and the world as we know it would not exist.

To the rescue comes quantum physics, which postulates that only very specific quantized energy states can exist in an atom. And suddenly atoms become stable again. Pew, lucky for us!

Do you want more from quantum mechanics than just your life? Ok, we have one more.

You may have heard that your CD and DVD readers use a laser to read of information from your disks. Did you know that the invention of lasers was only possible with the knowledge of quantum theory? One makes use of the same energy quantization in atoms we were talking about before. Interested in the details? Let us know and we may write a complete article about how lasers work.

It May Lead Us Towards A Multiverse

The idea that observation collapses the wave function and forces a quantum choice is known as the Copenhagen interpretation of quantum physics. However, its not the only option on the table. Advocates of the many worlds interpretation argue that there is no choice involved at all. Instead, at the moment the measurement is made, reality fractures into two copies of itself: one in which we experience outcome A, and another where we see outcome B unfold. It gets around the thorny issue of needing an observer to make stuff happen does a dog count as an observer, or a robot?

Instead, as far as a quantum particle is concerned, theres just one very weird reality consisting of many tangled-up layers. As we zoom out towards the larger scales that we experience day to day, those layers untangle into the worlds of the many worlds theory. Physicists call this process decoherence.

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What Is Quantum Physics In Three Sentences

Quantum Physics is physics that becomes specifically relevant for small particles, on the microscopic scale. For example for atoms, classical physics, that is the physics as was known before quantum physics, would provide wrong results. One problem of classical physics its prediction of unstable atoms is beautifully fixed by quantum physics, as we will discuss later.

Making Connections: Realms Of Physics

Workshop: Public Talk: The Many Worlds of Quantum ...

Classical physics is a good approximation of modern physics under conditions first discussed in the The Nature of Science and Physics. Quantum mechanics is valid in general, and it must be used rather than classical physics to describe small objects, such as atoms.

Atoms, molecules, and fundamental electron and proton charges are all examples of physical entities that are quantizedthat is, they appear only in certain discrete values and do not have every conceivable value. Quantized is the opposite of continuous. We cannot have a fraction of an atom, or part of an electrons charge, or 14-1/3 cents, for example. Rather, everything is built of integral multiples of these substructures. Quantum physics is the branch of physics that deals with small objects and the quantization of various entities, including energy and angular momentum. Just as with classical physics, quantum physics has several subfields, such as mechanics and the study of electromagnetic forces. The correspondence principle states that in the classical limit , quantum mechanics becomes the same as classical physics. In this chapter, we begin the development of quantum mechanics and its description of the strange submicroscopic world. In later chapters, we will examine many areas, such as atomic and nuclear physics, in which quantum mechanics is crucial.

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Other Interpretations Of Quantum Mechanics

There are over 20 interpretations of quantum mechanics: Copenhagen, Many Worlds, Bohmian, Transactional, etc. Many of them conflict.

Cartoon of the Many Worlds Interpretation of quantum mechanics.

The Many Worlds Interpretation, as an extreme example, provides a completely different interpretation of the equations of quantum mechanics. The Many Worlds Interpretation assumes that there are infinite numbers of universes. In each universe, particles always have only one position at any moment in time. In the universe in which we happen to reside, we can find its position. So can the residents of all the other universes.

The de Broglie-Bohmian Interpretation also assumes that particles only ever have one position, but doesnt go to the extreme of assuming an infinite number of universes. It imagines a wave of a new type of energy carrying the particle along like a surfer.

n the Transactional Interpretation, physical reality is only the tip of the iceberg.

The Transactional Interpretation*** holds that particles exist in a wavy sublevel of reality prior to detection. This wavy reality follows quantum laws. In accordance with these laws, probabilities interact with each other to determine what shows up in physical reality. Only upon detection, does a real particle enter physical reality.

A good analogy for the Transactional Interpretation is an iceberg. In our physical reality, we see the tip of the iceberg. But theres a lot going on beneath the surface.

The Copenhagen Interpretation And The Many

The two major interpretations of quantum theory’s implications for the nature of reality are the Copenhagen interpretation and the many-worlds theory. Niels Bohr proposed the Copenhagen interpretation of quantum theory, which asserts that a particle is whatever it is measured to be , but that it cannot be assumed to have specific properties, or even to exist, until it is measured. In short, Bohr was saying that objective reality does not exist. This translates to a principle called superposition that claims that while we do not know what the state of any object is, it is actually in all possible states simultaneously, as long as we don’t look to check.

To illustrate this theory, we can use the famous and somewhat cruel analogy of Schrodinger’s Cat. First, we have a living cat and place it in a thick lead box. At this stage, there is no question that the cat is alive. We then throw in a vial of cyanide and seal the box. We do not know if the cat is alive or if the cyanide capsule has broken and the cat has died. Since we do not know, the cat is both dead and alive, according to quantum law – in a superposition of states. It is only when we break open the box and see what condition the cat is that the superposition is lost, and the cat must be either alive or dead.

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What Is Quantum Physics

Quantum physics is a branch of science that focuses on systems explained by theories such as quantum mechanics and quantum field theory. Scientists and researchers focus on this area in order to use this knowledge to understand the behaviour of particles at the subatomic level. However, sometimes we use the terms quantum physics and quantum mechanics interchangeably.

Objects Can Be In Two Places At Once

Quantum Superposition Explained | Quantum Mechanics | Quantum Physics | Quantum Computing tutorial

Wave-particle duality is an example of superposition. That is, a quantum object existing in multiple states at once. An electron, for example, is both here and there simultaneously. Its only once we do an experiment to find out where it is that it settles down into one or the other.

This makes quantum physics all about probabilities. We can only say which state an object is most likely to be in once we look. These odds are encapsulated into a mathematical entity called the wave function. Making an observation is said to collapse the wave function, destroying the superposition and forcing the object into just one of its many possible states.

This idea is behind the famous Schrödingers cat thought experiment. A cat in a sealed box has its fate linked to a quantum device. As the device exists in both states until a measurement is made, the cat is simultaneously alive and dead until we look.

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What Is Quantum Entanglement

One of the key concepts is quantum entanglement, which describes a situation where multiple particles are associated in such a way that measuring the quantum state of one particle also places constraints on the measurements of the other particles. This is best exemplified by the EPR Paradox. Though originally a thought experiment, this has now been confirmed experimentally through tests of something known as Bell’s Theorem.

It Causes Black Holes To Evaporate

A quantum rule called the Heisenberg uncertainty principle says that its impossible to perfectly know two properties of a system simultaneously. The more accurately you know one, the less precisely you know the other. This applies to momentum and position, and separately to energy and time.

Its a bit like taking out a loan. You can borrow a lot of money for a short amount of time, or a little cash for longer. This leads us to virtual particles. If enough energy is borrowed from nature then a pair of particles can fleetingly pop into existence, before rapidly disappearing so as not to default on the loan.

Stephen Hawking imagined this process occurring at the boundary of a black hole, where one particle escapes , but the other is swallowed. Over time the black hole slowly evaporates, as its not paying back the full amount it has borrowed.

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Why Is Probability Important In Quantum Physics

One more thing. That theres a 50 percent probability that a tossed coin will land heads simply means that it has two sides and we have no way of knowing which way up it will land. This is a classical probability born of ignorance.

We can be confident that the coin continues to have two sides heads and tails as it spins through the air, but were ignorant of the exact details of its motion so we cant predict with certainty which side will land face up. In theory, we could, if we knew exactly how hard you flipped it at exactly what angle, and at exactly what height you would catch it.

Quantum probability is thought to be very different. When we toss a quantum coin we might actually be quite knowledgeable about most of the details of its motion, but we cant assume that heads and tails exist before the coin has landed, and we look.

So, it doesnt matter exactly how much information you have about the coin toss, you will never be able to say with any certainty what the result will be, because its not pre-determined like in a classical system.

Einstein deplored this seeming element of pure chance in quantum mechanics. He famously declared that: God does not play dice.

And then, in 1927, the debates began. What is the wave function and how should it be interpreted? What is quantum mechanics telling us about the nature of physical reality? And just what is this thing called reality, anyway?

Violations Of Bell’s Inequality

Consciousness and Quantum Mechanics wherein Plancks ...

Local hidden variable theories fail, however, when measurements of the spin of entangled particles along different axes are considered. If a large number of pairs of such measurements are made , then statistically, if the local realist or hidden variables view were correct, the results would always satisfy Bell’s inequality. A number of experiments have shown in practice that Bell’s inequality is not satisfied. However, prior to 2015, all of these had loophole problems that were considered the most important by the community of physicists. When measurements of the entangled particles are made in moving relativistic reference frames, in which each measurement occurs before the other, the measurement results remain correlated.

The fundamental issue about measuring spin along different axes is that these measurements cannot have definite values at the same timethey are incompatible in the sense that these measurements’ maximum simultaneous precision is constrained by the uncertainty principle. This is contrary to what is found in classical physics, where any number of properties can be measured simultaneously with arbitrary accuracy. It has been proven mathematically that compatible measurements cannot show Bell-inequality-violating correlations, and thus entanglement is a fundamentally non-classical phenomenon.

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Who Developed Quantum Mechanics

As scientists gained the technology to measure with greater precision, strange phenomena was observed. The birth of quantum physics is attributed to Max Planck’s 1900 paper on blackbody radiation. Development of the field was done by Max Planck, Albert Einstein, Niels Bohr, Richard Feynman, Werner Heisenberg, Erwin Schroedinger, and other luminary figures in the field. Ironically, Albert Einstein had serious theoretical issues with quantum mechanics and tried for many years to disprove or modify it.

Everything You Need To Know About Quantum Physics

Quantum physics is a branch of physics also known as quantum mechanics or quantum theory.

Mechanics is that part of physics concerned with stuff that moves, from cannonballs to tennis balls, cars, rockets, and planets. Quantum mechanics is that part of physics which describes the motions of objects at molecular, atomic, and sub-atomic levels, such as photons and electrons.

Although quantum mechanics is an extraordinarily successful scientific theory, on which much of our modern, tech-obsessed lifestyles depend, it is also completely mad.

Read more about quantum physics:

The theory quite obviously works, but it appears to leave us chasing ghosts and phantoms, particles that are waves and waves that are particles, cats that are at once both alive and dead, lots of seemingly spooky goings-on, and a desperate desire to lie down quietly in a darkened room.

If youve ever wondered what is it about quantum theory that makes it so baffling to many, heres a brief summary of quantum in simple terms.

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What Everyone Should Know About Quantum Physics

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In this article we let you know what we believe everyone should know about quantum physics. This includes you, even if science is not your favorite topic. We start simple, with questions about what quantum physics is and were the name comes from. Then we move on to more complex topics and conclude with how quantum physics affects your life. My life? you may wonder. Yes, really your life.

What Is Particle Physics

Quantum Computers, Explained With Quantum Physics

Particle physics is a branch of physics in which we study the nature of particles that constitute matter and radiation. The term particle may refer to different objects, but in particle physics, we usually talk about smallest detectable particles subatomic particles.

Subatomic particles include protons, neutrons, electrons, etc. that form from radioactive processes and scattering processes. Moreover, particle physics deal with the dynamics of these particles such as the wave-particle duality. They are useful concepts in studying the particles. The standard model presents the dynamics of the subatomic particles.

Figure 02: Standard Model of Elementary Particles

That is the standard model describes the classification of all subatomic particles and the strong, weak and electromagnetic fundamental interactions of these particles.

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Quantum Physics Vs Quantum Mechanics


Pengwuino said:One of my professors said that theorizing about something is physics, putting equations to it is mechanics.


Galileo said:The way I see it is that quantum physics is more general than quantum mechanics.Quantum physics is the name for a collection of quantum theories: relativistic quantum mechanics and quantum field theory.Just like classical physics is a collective name for classical mechanics, electromagnetism and relativity.

Galileo said:The way I see it is that quantum physics is more general than quantum mechanics.


We will use the term “quantum mechanics” to refer to both relativistic and non-relativistic quantum mechanics the terms quantum physics and quantum theory are synonymous. It should be noted, however, that certain authors refer to “quantum mechanics” in the more restricted sense of non-relativistic quantum mechanics.


Simonne said:I’m a Literature buff writing a health and diet book desperately trying to comprehend Quantum Physics so I can sum it up.

quantum physics = intermediate level, quantum mechanics = semi-advanced level,

A typical sequence of courses is: Quantum Physics Quantum Mechanics Quantum Field Theory. This gives the impression that quantum physics is less advanced than the others.

Wikipedia: the terms quantum physics and quantum theory are synonymous


rewebster said:I can be confused if I read this.

know the details

Quantum Physics May Be Even Spookier Than You Think

A new experiment hints at surprising hidden mechanics of quantum superpositions

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It is the central question in quantum mechanics, and no one knows the answer: What really happens in a superpositionthe peculiar circumstance in which particles seem to be in two or more places or states at once? In 2018 a team of researchers in Israel and Japan proposed an experiment that could finally let us say something for sure about the nature of this puzzling phenomenon.

Their experiment was designed to enable scientists to sneak a glance at where an objectin this case a particle of light, called a photonactually resides when it is placed in a superposition. And the researchers predict the answer will be even stranger and more shocking than two places at once.

The classic example of a superposition involves firing photons at two parallel slits in a barrier. One fundamental aspect of quantum mechanics is that tiny particles can behave like waves, so that those passing through one slit interfere with those going through the other, their wavy ripples either boosting or canceling one another to create a characteristic pattern on a detector screen. The odd thing, though, is this interference occurs even if only one particle is fired at a time. The particle seems somehow to pass through both slits at once, interfering with itself. Thats a superposition.

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