Quantum systems without a classical limit

Click For Summary
Quantum systems without a classical limit refer to systems that do not exhibit classical behavior even as they scale up in size. Examples include spin one-half particles and systems of coupled spin one-halfs. The concept challenges the notion that large quantum systems must eventually conform to classical physics. A white dwarf star exemplifies this idea, as it behaves quantum mechanically despite containing a vast number of particles, yet can transition to a classical state under certain conditions. The discussion highlights the complexity of defining classical limits in quantum mechanics.
wdlang
Messages
306
Reaction score
0
in the literature, people are talking about 'quantum systems without a classical limit'

could anyone give me an example?
 
Physics news on Phys.org
There are no examples given in "the literature" that you read?

Zz.
 
Spin one-half. Or a system of coupled spin one-halfs.
 
I'm not sure what is meant by "no classical limit." A white dwarf star in a sense is not a classical limit, even though it is a huge number of particles, but if you heat it up high enough it would explode and be a very classical type Ia supernova.
 

Thread 'Two equivalent statements of time reversal symmetric Hamiltonian'

Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?
View full post »

Similar threads

Undergrad Do ensemble-based predictions truly describe real finite systems?
  • · Replies 4 ·
Replies
4
Views
540
Graduate Multi-scale Decoherence and the Quantum-to-Classical Transition
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Could a quantum computer simulate any system based on different types of logic?
  • · Replies 2 ·
Replies
2
Views
1K
Undergrad Repeated measurements on a quantum system interacting with other quantum systems
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Schrödinger equation and classical wave equation
  • · Replies 39 ·
2
Replies
39
Views
2K
High School Frequency of an EM wave in Classical and Quantum Physics
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Let's talk about the classical limit of QM
  • · Replies 13 ·
Replies
13
Views
2K
Insights The Classical Limit of Quantum Mechanical Commutator
  • · Replies 8 ·
Replies
8
Views
3K
Graduate How useful are quantum-classical hybrid theories?
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad How Do Quantum Numbers Influence Energy Levels in Atomic Systems?
  • · Replies 15 ·
Replies
15
Views
2K