Description
Return trap displacement and force under a supplied sign.
Polymer elasticity and optical trapping relate small displacements or equilibrium fluctuations to an effective stiffness. A linear force law and a variance-based estimate depend on different assumptions; a supplied length or noise correction does not establish that a real system is harmonic or in equilibrium.
Return trap displacement and force under a supplied sign.
When to use this tool
Use Optical Trap Offset Force Term when evaluating the stated polymer or harmonic-trap term under its supplied assumptions.
How to use the tool and how it works
- Enter stiffness, measuredPosition, zeroPosition, suppliedForceSign. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read displacement, force. Use the output convention below.
Return trap displacement and force under a supplied sign. Require stiffness >= 0 and suppliedForceSign either -1 or +1; displacement = measuredPosition-zeroPosition, force = sign*stiffness*displacement.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| stiffness | Stiffness | Required. Finite number; minimum 0. |
| measuredPosition | Measured Position | Required. Finite number. |
| zeroPosition | Zero Position | Required. Finite number. |
| suppliedForceSign | Supplied Force Sign | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| displacement | Displacement | Required. Finite number. |
| force | Force | Required. Finite number. |
{
"input": {
"stiffness": 2,
"measuredPosition": 3,
"zeroPosition": 1,
"suppliedForceSign": -1
},
"output": {
"displacement": 2,
"force": -4
}
}Limitations and assumptions
- The sign and coordinate origin are assertions; the result does not validate instrument calibration or an actual force measurement.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use the appropriate complete polymer/trap model, calibrated observations and a justified equilibrium/noise analysis for physical parameter inference.
References
Similar or alternative tools
- Optical Trap Stiffness Variance Term
Return variance-corrected harmonic trap stiffness.
- Trap Force Displacement Residual
Return restoring-force prediction and residual.